soc: qcom: smd: Send interrupt only once from smd_packet_write

smd_packet_write raises interrupt after writing SMD header and packet
data. This causes the remote processor to get interrupted twice for same
data packet.

Raise the interrupt only once from smd_packet_write.

CRs-Fixed: 589565
Change-Id: I71b5c90b4e25c6161669bed2930875b3f1af6584
Signed-off-by: Zaheerulla Meer <zmeer@codeaurora.org>