spi: add mt8186-nor compatible string

Add MT8186 spi-nor controller support.
MT8186 needs a new clock name, axi_s, for spi nor axi slave bus clock.

Signed-off-by: Guochun Mao <guochun.mao@mediatek.com>
Signed-off-by: Zhen Zhang <zhen.zhang@mediatek.com>
Link: https://lore.kernel.org/r/20220118142820.2729-2-guochun.mao@mediatek.com


Signed-off-by: Mark Brown <broonie@kernel.org>