arm64: dts: qcom: sdm845-mtp: Relocate remoteproc firmware

Update the firmware-name of the remoteproc nodes to mimic the firmware
structure on other 845 devices.

Reviewed-by: Sibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20200302020757.551483-1-bjorn.andersson@linaro.org


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