soc: qcom: mem-buf: Do not print errors on probe deferrals

hh_msgq_register() can now return -EPROBE_DEFER as an error code.
Since this is not a fatal error, and will end up in having the
probe function called again at a later point in time, do not
print an error when -EPROBE_DEFER is returned.

Change-Id: I7646788719bdbaac309bc1fbd840de754398e23b
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>