MIPS: WRPPMC: Move code one directory level up.

It was the last platform under gt64120 and will fit better into the new
platform makefile scheme, if moved.
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/Makefile

@@ -194,7 +194,7 @@ include $(srctree)/arch/mips/Kbuild.platforms
 #
 # Wind River PPMC Board (4KC + GT64120)
 #
-core-$(CONFIG_WR_PPMC)		+= arch/mips/gt64120/wrppmc/
+core-$(CONFIG_WR_PPMC)		+= arch/mips/wrppmc/
 cflags-$(CONFIG_WR_PPMC)		+= -I$(srctree)/arch/mips/include/asm/mach-wrppmc
 load-$(CONFIG_WR_PPMC)		+= 0xffffffff80100000