regulator: Add Renesas RZ/G2L USB VBUS regulator driver

regulator: Add Renesas RZ/G2L USB VBUS regulator driver

As per the RZ/G2L HW manual, VBUSEN can be controlled by the VBOUT
bit of the VBUS Control Register. This register is mapped in the reset
framework. The reset driver expose this register as regmap and instantiates
this driver. The consumer will use the regulator API to control the VBOUT
bit as the control need to be done in the atomic context.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://patch.msgid.link/20240616105402.45211-5-biju.das.jz@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>