ALSA: Fix Trivial Warnining in sound/pci/cmipci.c

Fixed the compile warning below by initializatin iomidi variable properly.
  sound/pci/cmipci.c: In function ‘snd_cmipci_probe’:
  sound/pci/cmipci.c:3017: warning: ‘iomidi’ may be used uninitialized in this function

Signed-off-by: Subrata Modak <subrata@linux.vnet.ibm.com>
Cc: linux-pci <linux-pci@atrey.karlin.mff.cuni.cz>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Sachin P Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>