soc: qcom: smd: Reject send of too big packets

Attempting to find room for a packet that's bigger than the fifo will
never succeed and the calling process will be sleeping forever in the
loop, waiting for enough room. So fail early instead.

Reported-by: Courtney Cavin <courtney.cavin@sonymobile.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Reviewed-by: Andy Gross <agross@codeaurora.org>
Signed-off-by: Andy Gross <agross@codeaurora.org>