serial: pl011: Add reg-io-width parameters

Some of the implementations can read only 32 bits because of
the interface limitations of the port they are connected to.
Add a parameter reg-io-width for supporting such platforms.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@amd.com>
Link: https://lore.kernel.org/r/20220826120559.2122-3-shubhrajyoti.datta@amd.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>