remoteproc: qcom_q6v5_mss: Use devm_platform_ioremap_resource_byname() to simplify code

In this function, devm_platform_ioremap_resource_byname() should be
suitable to simplify code.

Signed-off-by: zhaoxiao <long870912@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210906071147.9095-1-long870912@gmail.com