soc: qcom: mem-buf: Limit the number of input ACL entries

The number of ACL entries is currently not sanitized, which
can allow for unreasonably large ACL to be allocated for
later processing. Allowing for this to happen doesn't make much
sense, as there aren't any valid usecases that require a large
ACL, so restrict the number of ACL entries to 16. Also, while we're
here, fix up some of the error handling in a few places.

Change-Id: I5d1371ed180608486bcde1e208a36782986313af
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>