build: add e5500 CPU_TYPE

This CPU type is compatible with NXP's PPC based QorIQ processors, and
will be used by the upcoming new qoriq target.

Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
Reviewed-by: Rui Salvaterra <rsalvaterra@gmail.com>

include/target.mk

@@ -234,6 +234,7 @@ ifeq ($(DUMP),1)
   endif
   ifeq ($(ARCH),powerpc64)
     CPU_TYPE ?= powerpc64
+    CPU_CFLAGS_e5500:=-mcpu=e5500
     CPU_CFLAGS_powerpc64:=-mcpu=powerpc64
   endif
   ifeq ($(ARCH),sparc)