mmc: rtsx: reset power state on suspend

mmc: rtsx: reset power state on suspend

When rtsx_pci suspends, the card reader hardware powers off but the sdmmc
driver's prev_power_state remains as MMC_POWER_ON. This causes sd_power_on
to skip reinitialization on the next I/O request, leading to DMA transfer
timeouts and errors on resume 20% of the time.

Add a power_off slot callback so the PCR can notify the sdmmc driver
during suspend. The sdmmc driver resets prev_power_state, and sd_request
checks this to reinitialize the card before the next I/O.

Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
Link: https://patch.msgid.link/20260105060236.400366-2-matthew.schwartz@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>