msm: subsystem_restart: Don't use phase 3 SSR on the SGLTE2

This change has already been done for the SGLTE target.
See commit e4ae75ea. The
current patch extends the change to the SGLTE2 target.
The original commit text follows.

On the SGLTE2 platform, phase 2 SSR is required to address
the dependency between the internal and external modems. The
other subsystems (RIVA, LPASS etc) still need to do an
independent restart. In the absence of a matching restart
order, a request for a subsystem restart on a subsystem will
be treated as an  independent phase-3 like restart, even if
the current restart_level is phase 2. Therefore, don't allow
phase 3 on SGLTE platforms.

Change-Id: I99469883e85f87a3b49846699c4b9d84cd385285
Signed-off-by: Joel King <joelking@codeaurora.org>