spi: pxa2xx: Remove pointer to chip data from driver data

Transfer state machine in this driver does not need to set/unset pointer
to chip data between queueing and finalizing message as it is not
actually used as a state info itself but just pointer passing.

Since this per SPI device specific chip data is already carried in
ctldata use that and remove pointer to chip data from driver data.

While at it, group initialized variables before uninitialized variables
in pump_transfers().

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