pistachio: don't open code ramstage loading

Use the run_ramstage() function to load and run ramstage.

Change-Id: I783801bf506fa2f9608eefe1cd20257292c80af5
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9148
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
2 files changed