ASoC: samsung: i2s: Add missing assignment of variant_regs

Add assignment of the variant_regs field which is missing in commit
a5a56871f8 ("ASoC: samsung: add support
for exynos7 I2S controller"). Without this attempting to probe the
secondary DAI fails with an error like:

[    1.763026] Unable to handle kernel NULL pointer dereference at virtual address 0000000c
[    1.780895] pgd = c0004000
[    1.783606] [0000000c] *pgd=00000000
[    1.838255] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[    1.843514] Modules linked in:
[    1.846558] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.18.0-rc1-00009-g5dcb01e-dirty #1521
[    1.854887] task: ee00a800 ti: ee088000 task.ti: ee088000
[    1.860284] PC is at i2s_txctrl+0x40/0x2d4
[    1.864350] LR is at i2s_txctrl+0x28/0x2d4
[    1.868428] pc : [<c036ffd4>]    lr : [<c036ffbc>]    psr: 60000153
[    1.868428] sp : ee089dc0  ip : 00000000  fp : ee21f000
[    1.879883] r10: 00000000  r9 : ee21fb00  r8 : c06406c4
[    1.885091] r7 : ee21fb00  r6 : 00000000  r5 : f00f6000  r4 : ed943410
[    1.891601] r3 : 0000016c  r2 : c0464550  r1 : c055cef8  r0 : ed943610
[    1.898113] Flags: nZCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment kernel
[    1.905490] Control: 10c5387d  Table: 4000404a  DAC: 00000015
[    1.911218] Process swapper/0 (pid: 1, stack limit = 0xee088240)
[    1.917208] Stack: (0xee089dc0 to 0xee08a000)
...
[    2.068431] [<c036ffd4>] (i2s_txctrl) from [<c03719fc>] (samsung_i2s_dai_probe+0xb8/0x450)
[    2.076676] [<c03719fc>] (samsung_i2s_dai_probe) from [<c03607e0>] (snd_soc_register_card+0xd98/0x1348)
[    2.086044] [<c03607e0>] (snd_soc_register_card) from [<c03726e4>] (odroidx2_audio_probe+0xa8/0x11c)
[    2.095160] [<c03726e4>] (odroidx2_audio_probe) from [<c0249dd0>] (platform_drv_probe+0x48/0xa4)
[    2.103922] [<c0249dd0>] (platform_drv_probe) from [<c0248988>] (driver_probe_device+0x10c/0x22c)
[    2.112773] [<c0248988>] (driver_probe_device) from [<c0248b34>] (__driver_attach+0x8c/0x90)
[    2.121192] [<c0248b34>] (__driver_attach) from [<c02471c8>] (bus_for_each_dev+0x54/0x88)
[    2.129352] [<c02471c8>] (bus_for_each_dev) from [<c0248188>] (bus_add_driver+0xd4/0x1d0)
[    2.137510] [<c0248188>] (bus_add_driver) from [<c024915c>] (driver_register+0x78/0xf4)
[    2.145499] [<c024915c>] (driver_register) from [<c0008924>] (do_one_initcall+0x80/0x1b8)
[    2.153670] [<c0008924>] (do_one_initcall) from [<c05b7d40>] (kernel_init_freeable+0xfc/0x1c8)
[    2.162260] [<c05b7d40>] (kernel_init_freeable) from [<c04146c0>] (kernel_init+0x8/0xec)
[    2.170330] [<c04146c0>] (kernel_init) from [<c000e7f8>] (ret_from_fork+0x14/0x3c)
[    2.177873] Code: e5940000 e59f128c e59f228c e2800010 (e59c700c)

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/samsung/i2s.c

@@ -1239,6 +1239,8 @@ static int samsung_i2s_probe(struct platform_device *pdev)
 			ret = -ENOMEM;
 			goto err;
 		}
+
+		sec_dai->variant_regs = pri_dai->variant_regs;
 		sec_dai->dma_playback.dma_addr = regs_base + I2STXDS;
 		sec_dai->dma_playback.ch_name = "tx-sec";