spi: dw: Remove DW DMA code dependency from DW_DMAC_PCI

spi: dw: Remove DW DMA code dependency from DW_DMAC_PCI

Since there is a generic method available to initialize the DW SPI DMA
interface on any DT and ACPI-based platforms, which in general can be
designed with not only DW DMAC but with any DMA engine on board, we can
freely remove the CONFIG_DW_DMAC_PCI config from dependency list of
CONFIG_SPI_DW_DMA. Especially seeing that we don't use anything DW DMAC
specific in the new driver.

Co-developed-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Co-developed-by: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Signed-off-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Signed-off-by: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20200529131205.31838-12-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>