ARM: dts: msm: Switch to UARTDM5 for MSM8992 Sim

Reconfigure the MSM8992 Simulator platform to use the
UARTDM5 instance (rather than UARTDM2) for its serial
console, to allow simplifing the earlyprintk selection
mechanism for multiple platforms.

Change-Id: I3f5b835b3322a9443768b93cacd97b28a4368f82
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>