intel: Turn `DEFAULT_RCBA` into a Kconfig symbol

Create `FIXED_RCBA_MMIO_BASE` and use it everywhere, except in cases
where a pointer cast would be necessary. Instances in Sandy Bridge MRC
code were left as-is intentionally, so as not to collide with another
cleanup patch train.

Tested with BUILD_TIMELESS=1, these boards remain identical:
- Asus P8Z77-V LX2
- Packard Bell MS2290

Change-Id: I642958fbd6f02dbf54812d6a75d6bc3087acc77a
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50036
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions