clk: en7523: Add EN7581 support

Introduce EN7581 clock support to clk-en7523 driver.
Add hw_init callback to en_clk_soc_data data structure.

Tested-by: Zhengping Zhang <zhengping.zhang@airoha.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/57b6e53ed4d2b2e38abff6a3ea56841bad6be8a9.1712399981.git.lorenzo@kernel.org


Signed-off-by: Stephen Boyd <sboyd@kernel.org>