Add the new GP1 PLL for the Amlogic SM1 SoC, used to feed the new
DynamIQ Shared Unit of the ARM Cores Complex.

This also adds a dedicated set of clock and compatible for SM1.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>