[ALSA] sound: fm801.c fix shadowed variable warning

id was only used as a counter in a for loop, move the declaration
to where it is used and change it to i.
sound/pci/fm801.c:1288:6: warning: symbol 'id' shadows an earlier one
sound/pci/fm801.c:51:13: originally declared here

[tiwai - fixed a coding style issue as well]

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>