soc: qcom: ocmem: Make use of the helper function devm_platform_ioremap_resource_byname()

Use the devm_platform_ioremap_resource_byname() helper instead of
calling platform_get_resource_byname() and devm_ioremap_resource()
separately

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210908080216.1301-2-caihuoqing@baidu.com