spi/pl022: fix up differences between ARM and ST versions

The PL022 SPI driver did not cleanly separate between the
original unmodified ARM version and the ST Microelectronics
versions. Split this more cleanly and fix some whitespace
moaning from checkpatch at the same time.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>