ALSA: es1968: Add error handling for snd_pcm_hw_constraint_pow2()

ALSA: es1968: Add error handling for snd_pcm_hw_constraint_pow2()

The function snd_es1968_capture_open() calls the function
snd_pcm_hw_constraint_pow2(), but does not check its return
value. A proper implementation can be found in snd_cx25821_pcm_open().

Add error handling for snd_pcm_hw_constraint_pow2() and propagate its
error code.

Fixes: b942cf815b57 ("[ALSA] es1968 - Fix stuttering capture")
Cc: stable@vger.kernel.org # v2.6.22
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20250514092444.331-1-vulab@iscas.ac.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>