target/mips: only build mips-semi for softmmu

The is_uhi gates all semihosting calls and always returns false for
CONFIG_USER_ONLY builds. There is no reason to build and link
mips-semi for these builds so lets fix that.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

target/mips/Makefile.objs

@@ -1,4 +1,5 @@
 obj-y += translate.o dsp_helper.o op_helper.o lmi_helper.o helper.o cpu.o
-obj-y += gdbstub.o msa_helper.o mips-semi.o
+obj-y += gdbstub.o msa_helper.o
+obj-$(CONFIG_SOFTMMU) += mips-semi.o
 obj-$(CONFIG_SOFTMMU) += machine.o cp0_timer.o
 obj-$(CONFIG_KVM) += kvm.o

target/mips/helper.h

@@ -2,7 +2,9 @@ DEF_HELPER_3(raise_exception_err, noreturn, env, i32, int)
 DEF_HELPER_2(raise_exception, noreturn, env, i32)
 DEF_HELPER_1(raise_exception_debug, noreturn, env)
 
+#ifndef CONFIG_USER_ONLY
 DEF_HELPER_1(do_semihosting, void, env)
+#endif
 
 #ifdef TARGET_MIPS64
 DEF_HELPER_4(sdl, void, env, tl, tl, int)

target/mips/translate.c

@@ -13726,6 +13726,14 @@ static inline bool is_uhi(int sdbbp_code)
 #endif
 }
 
+#ifdef CONFIG_USER_ONLY
+/* The above should dead-code away any calls to this..*/
+static inline void gen_helper_do_semihosting(void *env)
+{
+    g_assert_not_reached();
+}
+#endif
+
 static int decode_mips16_opc (CPUMIPSState *env, DisasContext *ctx)
 {
     int rx, ry;