msm: qdsp6v2: convert superfluous pr_err to pr_debug

Drivers should be silent under normal operation, however there is
currently a pr_err on a non-error path in the qdsp6v2 code. Convert it
to a pr_debug.

Change-Id: I0a4f0f51d0a21ef63f386cc7a831587b219e930d
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>