soc: qcom: socinfo: simplify searching for smem regions

Instead calling smem_find() repeatedly with different sizes
for SMEM_HW_SW_BUILD_ID, call smem_get_entry() which returns
a pointer to the region regardless of its size.

Change-Id: If68ab31f808e2ecb740e1560ec5d9a7edd9a8c9f
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>