ALSA: emu10k1: remove redundant assignment to tmp

The assignment to variable tmp is redundant as the value is never
read and a new value is assigned to tmp in the following for-loop,
so remove the assignment.
Cleans up clang warning: Value stored to 'tmp' is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>