drivers: gpio: Add MAX14916 industrial output

Industrial 8 channel output with advanced diagnostics.
Allowing giagnostic configuration both on per channel or global bases
In SPI communication diagnostic status transmitted on every
READ/WRITE which includes generic status of chip.
Diagnostics includes :
 * Oveload
 * Open Wire
 * Over current
 * Short to VDD
 * Thermal Shutdown
 * VDD Warn
 * Watch Dog Error
 * Communication Error
 * VDD under voltage

Add app.overlay for MAX14916 driver.

Tested with adopted basic/blinky example.

Signed-off-by: Stoyan Bogdanov <sbogdanov@baylibre.com>