mmc: dw_mmc: add common capabilities to replace caps

The caps field depends on the mshcN alias ID but for some devices this
is unnecessary as the capabilities are the same for all instances
sharing the same compatible.

Add a common_caps field for this case which updates the host's
capabilities without needing the mshcN alias ID.

Signed-off-by: John Keeping <john@metanate.com>
Tested-by: Nicolas Frattaroli <frattaroli.nicolas@gmail.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Link: https://lore.kernel.org/r/20211124184603.3897245-2-john@metanate.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>