clk: vc5: Add support for IDT VersaClock 5P49V5925

Update IDT VersaClock 5 driver to support 5P49V5925. This chip has only
external clock input, four fractional dividers (FODs) and five clock
outputs (four universal clock outputs and one reference clock output at
OUT0_SELB_I2C).

Signed-off-by: Vladimir Barinov <vladimir.barinov+renesas@cogentembedded.com>
Reviewed-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>