arm64: dts: qcom: use generic sram as name for imem and ocmem nodes

According to Devicetree specification, the device nodes should be
generic, reflecting the function of the device.  The typical name for
memory regions is "sram".

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20220607171848.535128-8-krzysztof.kozlowski@linaro.org