AudioFlinger: return actual MMAP stream configuration after opening

Fix MmapStreamInterface::openMmapStream() implementation to return
actual sampling rate, channel mask and format used at the audio HAL
once the stream is opened.

Bug: 76213894
Test: make
Change-Id: I0e497b898d86246bcb1bdde42c3114d43e1f14d0
1 file changed