spi: spi-pxa2xx: Remove unused legacy PXA DMA API channel numbers
These became unused by the commit 6356437e65c2
("spi: spi-pxa2xx: remove legacy PXA DMA bits").
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>