armv7: Clean up arm/snow bootblock build process.

Remove duplicated / testing code and share more driver for bootblock, romstage
and ramstage.

The __PRE_RAM__ is now also defined in bootblock build stage, since bootblock is
executed before RAM is initialized.

Change-Id: I4f5469b1545631eee1cf9f2f5df93cbe3a58268b
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: http://review.coreboot.org/2282
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
18 files changed