spi: lantiq: Move interrupt configuration to SoC specific data structure

Moving interrupt configuration to SoC specific data structure helps to add
support for newer SoCs on which SPI controller with lesser interrupt lines
compared to existing chipsets.

Signed-off-by: Dilip Kota <eswara.kota@linux.intel.com>
Link: https://lore.kernel.org/r/7eb6d863515245fedfa0296c72082df107367d07.1594957019.git.eswara.kota@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>