leds: aw200xx: Support HWEN hardware control

leds: aw200xx: Support HWEN hardware control

HWEN is hardware control, which is used for enable/disable aw200xx chip.
It's high active, internally pulled down to GND.

After HWEN pin set high the chip begins to load the OTP information,
which takes 200us to complete. About 200us wait time is needed for
internal oscillator startup and display SRAM initialization. After
display SRAM initialization, the registers in page 1 to page 5 can be
configured via i2c interface.

Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.com>
Link: https://lore.kernel.org/r/20231125200519.1750-3-ddrokosov@salutedevices.com
Signed-off-by: Lee Jones <lee@kernel.org>