mmc: mmci: increase stm32 sdmmcv2 clock max freq

The variant->f_max is dependent on the IP, not on the SoC where it is
embedded. Set the max frequency of its source clock to 267MHz.
The frequency used will be limited by the IOs max frequency, set in the
SoC device tree.

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20211215141727.4901-3-yann.gautier@foss.st.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>