cnss2: Dot not post work event from force RDDM function

The force RDDM function may be called from any serialized work event.
If it posts another work event and waits for it to complete, the new
work event will be blocked by current one and results deadlock. Avoid
posting the assert firmware work event by directly calling the event
handler and honoring the return code properly.

Change-Id: I08beab6f72319df96a26fc95e4294926d6a3c25f
Signed-off-by: Yue Ma <yuem@codeaurora.org>