cpu/amd/model_10xxx: Increase preram buffer size to 32k

This resolves an issue where large sections of the cbmem logs
were being dropped on AMD Fam10h boards.

Change-Id: I0e4e86e169aa4f20f06472f1a6e3136705ae4f9d
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/8851
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/cpu/amd/model_10xxx/Kconfig

@@ -72,4 +72,9 @@ config UDELAY_LAPIC_FIXED_FSB
 	int
 	default 200
 
+config CONSOLE_PRERAM_BUFFER_SIZE
+	hex
+	default 0x0 if CONSOLE_PRERAM_BUFFER_BASE = 0xabadbeef
+	default 0x8000
+
 endif	# CPU_AMD_MODEL_10XXX