ALSA: Fix memory leak on error in snd_compr_set_params()

If copy_from_user() does not return 0 we'll leak the memory we
allocated for 'params' when that variable goes out of scope.

Also a small CodingStyle cleanup: Use braces on both branches of
if/else when one branch needs it.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Acked-by: Vinod Koul <vinod.koul@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>