compress: Add non-blocking I/O

compress: Add non-blocking I/O

Support for non-blocking I/O, based on API of main alsalib.
In non-blocking mode a compress_write() will return without
blocking after it has written all bytes that will fit in the
buffer and compress_read() will return after it has read all
bytes available from the buffer. Use compress_wait() to wait
for free write space or available read bytes.

Non-blocking mode is enabled and disabled using compress_nonblock().

Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>