soc: qcom: smd: Correct fBLOCKREADINTR handling

fBLOCKREADINTR is masking the notification from the remote and should
hence be cleared while we're waiting the tx fifo to drain. Also change
the reset state to mask the notification, as send is the only use case
where we're interested in it.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Andy Gross <agross@codeaurora.org>