spi: pxa2xx: Convert to generalized SPI controller API

Convert to generalized SPI controller API introduced by the
commit 8caab75f

 ("spi: Generalize SPI "master" to "controller"").
Inside driver variable name "master" is still used to indicate the driver
is master only.

While at it, change "unsigned cs" to "unsigned int cs" in
pxa2xx_spi_fw_translate_cs() to suppress checkpatch warning.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>