phy: cadence: torrent: Constify regmap_config structs

The regmap_config structs are never modified and can be made const to
allow the compiler to put them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200912204639.501669-4-rikard.falkeborn@gmail.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>