cpu/intel/em64t101: Add Nehalem to compatibility list

Change-Id: I15a1c824b92e18f9963c60659ead92c988d1239b
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36588
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/include/cpu/intel/em64t101_save_state.h

@@ -20,6 +20,7 @@
 
 /* Intel Revision 30101 SMM State-Save Area
  * The following processor architectures use this:
+ * - Nehalem
  * - SandyBridge
  * - IvyBridge
  * - Haswell