spi: cadence-quadspi: clean up disable runtime pm quirk

spi: cadence-quadspi: clean up disable runtime pm quirk

Commit 30dbc1c8d50f ("spi: cadence-qspi: defer runtime support on
socfpga if reset bit is enabled") fixed a warm reset issue on SoCFPGA by
disabling runtime PM on that platform.

Clean up the quirk implementation by never dropping the runtime PM usage
count on probe instead of sprinkling conditionals throughout the driver
which makes the code unnecessarily hard to read and maintain.

Cc: Khairul Anuar Romli <khairul.anuar.romli@altera.com>
Cc: Adrian Ng Ho Yin <adrianhoyin.ng@altera.com>
Cc: Niravkumar L Rabara <nirav.rabara@altera.com>
Cc: Matthew Gerlach <matthew.gerlach@altera.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://patch.msgid.link/20260421125354.1534871-6-johan@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>