In the ST-Ericsson version of the PL011 the TX and RX have different
control registers.

Cc: Alessandro Rubini <rubini@unipv.it>
Signed-off-by: NMarcin Mielczarczyk <marcin.mielczarczyk@tieto.com>
Signed-off-by: NLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>