char: msm_smd_pkt: use open timeout for opening existing channel

If an SMD channel already exists, a default timeout of 2 seconds is used
instead of the opening timeout even though some clients need the
configured timeout.

Change code to use the opening timeout for all operations leading up to
the fully-opened state for the SMD channel.

CRs-Fixed: 755650
Change-Id: Id47aa057c3204f88ba55ae98d6c9e6d89c925cce
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>