[FM] There is no sound in speaker while playing FM in speaker mode

Launch FM and play a station -> Plug out headphones
-> Plug in headphones -> Switch to speaker mode, There
is no sound via speaker.

The fix is to let FM sound output via speaker.

from: https://partner-android-review.googlesource.com/#/c/192523/3


Bug 18795162

Change-Id: I16fce6914ea0b3d463c1205708d11265925097e4
Signed-off-by: Benson Huang <benson.huang@mediatek.com>