x86: link romstage and ramstage with 1 file

To reduce file clutter merge romstage.ld and ramstage.ld
into a single memlayout.ld. The naming is consistent with
other architectures and chipsets for their linker script
names. The cache-as-ram linking rules are put into a separate
file such that other rules can be applied for future verstage

TEST=Built rambi and dmp/vortex86ex.

Change-Id: I1e8982a6a28027566ddd42a71b7e24e2397e68d2
Signed-off-by: Aaron Durbin <adubin@chromium.org>
Reviewed-on: http://review.coreboot.org/11521
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
5 files changed