[ALSA] sound/pci: Drop unnecessary continue

Continue is not needed at the bottom of a loop.
The semantic patch implementing this change is as follows:
@@
@@
for (...;...;...) {
   ...
   if (...) {
     ...
-   continue;
   }
}

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>