mtd: spi-nor: support vcc-supply regulator

mtd: spi-nor: support vcc-supply regulator

SPI NOR flashes needs power supply to work properly. The power supply
maybe software controllable per board design. So add the support
for an vcc-supply regulator.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
[ta: move devm_regulator_get_enable() to spi_nor_probe().]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Signed-off-by: Pratyush Yadav <pratyush@kernel.org>
Link: https://lore.kernel.org/r/20241111111946.9048-3-tudor.ambarus@linaro.org