gpio: Add GPIO delay driver

gpio: Add GPIO delay driver

Add a GPIO controller driver that provides configurable delays when
setting GPIO output values. This is useful for hardware that requires
specific timing delays during power sequencing or GPIO state changes.

The driver wraps underlying GPIO controllers and adds programmable
ramp-up and ramp-down delays specified in microseconds through the
device tree. Each GPIO can have independent delay timings.

Device tree binding matches Linux.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/575998efc6ba0e405640789cf8d05f0b633f496e.1770105146.git.michal.simek@amd.com