The Linux bindings of the AEMIF offer properties that specify the
transaction timings for each chips select.

Add parsing of these properties to calculate the chip select's
configuration from them and the rate of the AEMIF's reference clock.

Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>

The AEMIF's bindings in the Linux tree have a node for the AEMIF
controller and then a node for each AEMIF's chip select. This CS node
doesn't have a compatible property but describes the timing parameters
used by a given chip select.
The U-Boot DM framework expects every node to have a 'compatible'
property. If no 'compatible' is present in a node, its children won't be
parsed by u-boot.

Add DM support to the ti-aemif driver.
Add a new ti-aemif-cs driver to comply with the Linux bindings and the
U-Boot's DM philosophy. This driver handles the timing parameters
of an AEMIF's chip select so move aemif_cs_configure() from ti-aemif.c
to ti-aemif-cs.c.

Signed-off-by: Bastien Curutchet <bastien.curutchet@bootlin.com>