H3 supports two SPI controllers. Four pins (MOSI, MISO, SCLK, SS) are
configured through the pinctrl subsystem.

Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Milo Kim <woogyom.kim@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>