This adds a struct for registers along with some bits from ATF to
the generic PL011 driver. It also adds a naive implementation of
uart_tx_flush() which was previously stubbed out.
Change-Id: Iee3fc6308cb92ad784e5ff3ac3a6e995d535be65
Signed-off-by: David Hendricks <dhendricks@fb.com>
Reviewed-on: https://review.coreboot.org/23031
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>