[ALSA] sound: emuproc.c fix signedness warning

Reading regs from the fpga into an int instead of a u32, trivial
fix.
sound/pci/emu10k1/emuproc.c:422:34: warning: incorrect type in argument 3 (different signedness)
sound/pci/emu10k1/emuproc.c:422:34:    expected unsigned int [usertype] *value
sound/pci/emu10k1/emuproc.c:422:34:    got int *<noident>

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