soc/amd/picasso: Increase SMM_RESERVED_SIZE

Correct a message of "Error: Can't add stage_cache 57a9e101 to imd".
ramstage is 0xffc90 and adding FSP-S (0x50000) failed.  Increase the
reserved region of SMRAM to accommodate both images.

BUG=b:158704095
TEST=Boot Mandolin and check console log

Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Change-Id: I51595d80d4779e995ec2a26e395cf95d666a309e
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42314
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/picasso/Kconfig b/src/soc/amd/picasso/Kconfig
index 725bd16..27901ba 100644
--- a/src/soc/amd/picasso/Kconfig
+++ b/src/soc/amd/picasso/Kconfig
@@ -284,7 +284,7 @@
 
 config SMM_RESERVED_SIZE
 	hex
-	default 0x150000
+	default 0x180000
 
 config SMM_MODULE_STACK_SIZE
 	hex