wave: add <time.h> missing header inclusion

[GitHub pull_request - opened <github@alsa-project.org>]

alsa-project/tinycompress pull request #38 was opened from bkuhls:

When compiling tinycompress with some libc other than glibc (e.g. musl libc), compilation fails with the following error:
```
    In file included from wave.c:11:0:
    /path/to/gcc/sysroot/usr/include/sound/asound.h:404:18: error: field 'trigger_tstamp' has incomplete type
      struct timespec trigger_tstamp; /* time when stream was started/stopped/paused */
    [...]
```
According to POSIX, "struct timespec" is defined in <time.h>. See: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/time.h.html

This patch fixes this build failure by including <time.h> prior <sound/asound.h>.

Request URL   : https://github.com/alsa-project/tinycompress/pull/38
Patch URL     : https://github.com/alsa-project/tinycompress/pull/38.patch
Repository URL: https://github.com/alsa-project/tinycompress