model_106cx: don't blindly set Kconfig settings

The CPU_ADDR_BITS was being unconditionally set.
Don't do that.

BUG=None
BRANCH=None
TEST=Built bayleybay and can now set CPU_ADDR_BITS properly.

Change-Id: Idbc63328fade8f5f05f7f46282139b86e6694989
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/169711
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
diff --git a/src/cpu/intel/model_106cx/Kconfig b/src/cpu/intel/model_106cx/Kconfig
index e26bf1f..7516106 100644
--- a/src/cpu/intel/model_106cx/Kconfig
+++ b/src/cpu/intel/model_106cx/Kconfig
@@ -7,7 +7,10 @@
 	select AP_IN_SIPI_WAIT
 	select TSC_SYNC_MFENCE
 
+if CPU_INTEL_MODEL_106CX
+
 config CPU_ADDR_BITS
 	int
 	default 32
 
+endif