clk: si5341: Allow different output VDD_SEL values

The driver was not previously programming the VDD_SEL values for each
output to indicate what external VDDO voltage was used for each. Add
ability to specify a regulator supplying the VDDO pin for each output of
the device. The voltage of the regulator is used to automatically set the
VDD_SEL value appropriately. If no regulator is specified and the chip is
being reconfigured, assume 2.5V which appears to be the chip default.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Link: https://lore.kernel.org/r/20210325192643.2190069-7-robert.hancock@calian.com


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