memory: omap-gpmc: wait pin additions

This patch introduces support for setting the wait-pin polarity as well
as using the same wait-pin for different CS regions.

The waitpin polarity can be configured via the WAITPIN<X>POLARITY bits
in the GPMC_CONFIG register. This is currently not supported by the
driver. This patch adds support for setting the required register bits
with the "ti,wait-pin-polarity" dt-property.

The wait-pin can also be shared between different CS regions for special
usecases. Therefore GPMC must keep track of wait-pin allocations, so it
knows that either GPMC itself or another driver has the ownership.

Signed-off-by: Benedikt Niedermayr <benedikt.niedermayr@siemens.com>
Link: https://lore.kernel.org/r/20221102133047.1654449-2-benedikt.niedermayr@siemens.com


Reviewed-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>