spi: enable the SpacemiT K1 SoC QSPI

Merge series from Alex Elder <elder@riscstar.com>:

This series adds support for the SpacemiT K1 SoC QSPI.  This IP is
generally compatible with the Freescale QSPI driver, requiring three
minor changes to enable it to be supported.  The changes are:
  - Adding support for optional resets
  - Having the clock *not* be disabled when changing its rate
  - Allowing the size of storage blocks written to flash chips
    to be set to something different from the AHB buffer size