pinctrl: qcom: spmi-mpp: Add PM8226 compatible

The PM8226 provides 8 MPPs.
Add a compatible to support them.

Signed-off-by: Rayyan Ansari <rayyan@ansari.sh>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220124171538.18088-2-rayyan@ansari.sh


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>