AMD agesa: add enable cache at the end of disable_cache_as_ram

add this code according to src/include/cpu/x86/cache.h ,line 92,
functin enable_cache()

Change-Id: Ida96a98397eeed98dd61ca979e8c5a33bf00f9e5
Signed-off-by: Siyuan Wang <SiYuan.Wang@amd.com>
Signed-off-by: Siyuan Wang <wangsiyuanbuaa@gmail.com>
Reviewed-on: http://review.coreboot.org/1662
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marcj303@gmail.com>

src/cpu/amd/agesa/cache_as_ram.inc

@@ -96,10 +96,14 @@ disable_cache_as_ram:
 
   AMD_DISABLE_STACK
 
+  /* enable cache */
+  movl %cr0, %eax
+  andl $0x9fffffff, %eax
+  movl %eax, %cr0
+  xorl %eax, %eax
+
   /* Restore the return stack */
   movd %xmm0, %esp
   ret
 
 cache_as_ram_setup_out:
-
-