soc: qcom: smem: Support getting cached entries

On msm8996 cached SMEM items are used for storing the GLINK FIFOs, so
for items not found in the uncached list we need to also search the
cased list for these items.

Change-Id: I27ae3e165a592a5f4e7d9aa10095646a99642ef8
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Patch-mainline: linux-arm-msm @ 14/08/17, 14:29
Signed-off-by: Chris Lew <clew@codeaurora.org>