Revert "aplay: fix pcm_read() return value"

Revert "aplay: fix pcm_read() return value"

This reverts commit 8aa13eec80eac312e4b99423909387660fb99b8f.

The semantics for pcm_read() and pcm_readv() was changed, but the
callers expect the exact frame count as requested. It's possible
to fix callers, but the fix is more complicated than to revert the
change. Note that '-d' processing was broken in some cases.

Note: The reverted commit allows that the return value might be
greater than requested (see the first condition in read routines).