soc: qcom: smem: Read version by using the smem header

The SMEM header structure includes the version information.
Read the version directly from the header instead of getting
an item from the global heap.

Change-Id: I74ce62b52c41b8f8a1705b9dd5e25a587236fa12
Signed-off-by: Chris Lew <clew@codeaurora.org>