ARM: dts: msm8974: Add modem remoteproc node

Add the remoteproc node for the modem on msm8974.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
[luca@z3ntu.xyz: cleanups, add label to smd-edge node]
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
Link: https://lore.kernel.org/r/20191114175348.288976-1-luca@z3ntu.xyz


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