cpu: fix cpu_microcode class

There's no reason defining another class compiler which
overrides the first one. The microcode files are just
built into a binary and added to cbfs. There's no reason to
change compilers.

Change-Id: Icb47d509832e7433092a814bad020f8d66f2a299
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11596
Reviewed-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Tested-by: build bot (Jenkins)
diff --git a/src/cpu/Makefile.inc b/src/cpu/Makefile.inc
index d757c79..3ea42e5 100644
--- a/src/cpu/Makefile.inc
+++ b/src/cpu/Makefile.inc
@@ -13,7 +13,6 @@
 subdirs-$(CONFIG_CPU_QEMU_X86) += qemu-x86
 
 $(eval $(call create_class_compiler,cpu_microcode,x86_32))
-$(eval $(call create_class_compiler,cpu_microcode,x86_64))
 ################################################################################
 ## Rules for building the microcode blob in CBFS
 ################################################################################