soc: qcom: fix out of bounds read issue

If userspace sends non-null terminated channel name then
out of bounds read is possible while printing channel name.
Fix this issue by validating channel name before use.

Change-Id: I418b7f446c6a849450dd4314592c1d3810163bdc
Signed-off-by: Vidyakumar Athota <vathota@codeaurora.org>