regulator: Add Richtek RT4803 boost regulator

RT4803 is a boost converter that integrates an internal bypass FET. It
will automatically transform the operation mode between bypass and boost
based on the voltage difference of the input and output voltage.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Link: https://lore.kernel.org/r/1680050606-461-2-git-send-email-cy_huang@richtek.com
Signed-off-by: Mark Brown <broonie@kernel.org>