Fix the build when srcdir == objdir

You would only see this error on a fresh clone when srcdir == objdir.  configure
will fail because roms/pcbios doesn't exist.

git submodule integration doesn't cleanup very well when switching between
branches so you'll get an roms/pcbios directory from normal operations if you
switch between old branches.

Thanks to a mistake in configure, if you build outside of srcdir, you'll also
get a valid roms/pcbios.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

configure

@@ -2534,12 +2534,12 @@ done # for target in $targets
 # build tree in object directory if source path is different from current one
 if test "$source_path_used" = "yes" ; then
     DIRS="tests tests/cris slirp audio block net pc-bios/optionrom"
-    DIRS="$DIRS roms/pcbios roms/seabios roms/vgabios"
+    DIRS="$DIRS roms/seabios roms/vgabios"
     FILES="Makefile tests/Makefile"
     FILES="$FILES tests/cris/Makefile tests/cris/.gdbinit"
     FILES="$FILES tests/test-mmap.c"
     FILES="$FILES pc-bios/optionrom/Makefile pc-bios/keymaps pc-bios/video.x"
-    FILES="$FILES roms/pcbios/Makefile roms/seabios/Makefile roms/vgabios/Makefile"
+    FILES="$FILES roms/seabios/Makefile roms/vgabios/Makefile"
     for bios_file in $source_path/pc-bios/*.bin $source_path/pc-bios/*.dtb $source_path/pc-bios/openbios-*; do
         FILES="$FILES pc-bios/`basename $bios_file`"
     done
@@ -2554,7 +2554,7 @@ if test "$source_path_used" = "yes" ; then
 fi
 
 # temporary config to build submodules
-for rom in seabios vgabios pcbios; do
+for rom in seabios vgabios ; do
     config_mak=roms/$rom/config.mak
     echo "# Automatically generated by configure - do not modify" >> $config_mak
     echo "SRC_PATH=$source_path/roms/$rom" >> $config_mak