[MIPS] MIPSsim: Fix cflags

Signed-off-by: NYoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/Makefile

@@ -328,7 +328,7 @@ load-$(CONFIG_MIPS_SEAD)	+= 0xffffffff80100000
 # MIPS SIM
 #
 core-$(CONFIG_MIPS_SIM)		+= arch/mips/mipssim/
-cflags-$(CONFIG_MIPS_SIM)	+= -Iinclude/asm-mips/mach-sim
+cflags-$(CONFIG_MIPS_SIM)	+= -Iinclude/asm-mips/mach-mipssim
 load-$(CONFIG_MIPS_SIM)		+= 0x80100000
 
 #