msm: smd: Remove usage of modem_notifier

The modem_notifier driver has no active clients so the calls
to modem_notifier APIs has no effect. As a cleanup task remove
the modem_notifer dependency from SMD driver.

Change-Id: I1b8bc9e0b1bafd60c1d0f14fe030da5bc3c8f55f
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>