spi: meson-spicc: support max 80MHz clock

The SPICC controller in Meson-AXG is capable of running at 80M clock.
The ASIC IP is improved and the clock is actually running higher than
previous old SoCs.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Yixun Lan <yixun.lan@amlogic.com>
Signed-off-by: Sunny Luo <sunny.luo@amlogic.com>
Link: https://lore.kernel.org/r/20200312133131.26430-5-narmstrong@baylibre.com


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