ARM: dts: msm: Update uartdm compatible strings

Let's follow the ratified DT binding and use uartdm instead of
hsuart. This does break backwards compatibility but this
shouldn't be a problem because the uart driver isn't probing on
these devices without adding clock support (which isn't merged so
far).

Cc: David Brown <davidb@codeaurora.org>
Acked-by: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>