p54spi: Kconfig option for config blob

This patch adds an Kconfig option, which allows the user
to select, whenever he/she wants to include a 4k blob for
generic calibration and interface values into the driver,
or cut the module size by about 15 to 20%.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>