Enable the MStar msg2638 touchscreen.

Reviewed-by: Stephan Gerhold <stephan@gerhold.net>
Signed-off-by: Vincent Knecht <vincent.knecht@mailoo.org>
Link: https://lore.kernel.org/r/20210528114345.543761-1-vincent.knecht@mailoo.org


Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>