cpu/amd: Detect any conflicts between sysinfo and the stack region

When increasing the number of supported CPUs on AMD Family 10h/15h
systems there is a relatively high chance of causing a collision
between the CAR global variable region and the AP stack space.
Such collision was noted when increasing the number of supported
CPUs to 32 on the ASUS KGPE-D16.

Detect collision at runtime and print a warning if collision is
present.

Change-Id: Ib5c32f868b1dfffb3b840bb1b1df5f55b5a25f8d
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/10401
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>

src/cpu/amd/geode_lx/Kconfig

@@ -19,6 +19,14 @@ config DCACHE_RAM_SIZE
 	hex
 	default 0x8000
 
+config DCACHE_BSP_STACK_SIZE
+	hex
+	default 0x2000
+
+config DCACHE_AP_STACK_SIZE
+	hex
+	default 0x400
+
 config GEODE_VSA
 	bool
 	default y