wifi: avoid crash when no phy's are found

Exit gracefully when no phy's are found.

Change-Id: I8c1f57e60bb63b52d8cb086e1a25d8d5b33f03f0
Signed-off-by: Vishal Mahaveer <vishalm@ti.com>
Merge "wifi: avoid crash when no phy's are found" into android-4.4