phy: amlogic: enable/disable clkin during Amlogic USB PHY init/exit

Previously, all Amlogic boards used the XTAL clock as the default board
clock for the USB PHY input, so there was no need to enable it.
However, with the introduction of new Amlogic SoCs like the A1 family,
the USB PHY now uses a gated clock. Hence, it is necessary to enable
this gated clock during the PHY initialization sequence, or disable it
during the PHY exit, as appropriate.

Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20230426102922.19705-2-ddrokosov@sberdevices.ru
Signed-off-by: Vinod Koul <vkoul@kernel.org>