regmap: Drop early readability check

We have some drivers that have a use case for cached write only
registers, doing read/modify/writes on read only registers in order to
work more easily with bitfields.  Go back to trying the cache before we
check if we can read from the device.

Fixes: eab5abde ("regmap: Check for register readability before checking cache during read")
Reported-by: Konrad Dybcio <konradybcio@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230615-regmap-drop-early-readability-v1-1-8135094362de@kernel.org


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