x86: Configure premem cbmem console size

Sometime preram cbmem logs are truncated due to lack of
space (default preram cbmem console size is 0xc00).

Provide Kconfig option to configure preram cbmem console
size so that mainboard can configure it to required value.

Change-Id: I221d9170c547d41d8bd678a3a8b3bca6a76ccd2e
Signed-off-by: Naresh G Solanki <naresh.solanki@intel.com>
Reviewed-on: https://review.coreboot.org/17839
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2 files changed