ALSA: asihpi: fix iounmap in error handler

ALSA: asihpi: fix iounmap in error handler

clang static analysis flags this problem
hpioctl.c:513:7: warning: Branch condition evaluates to
  a garbage value
                if (pci.ap_mem_base[idx]) {
                    ^~~~~~~~~~~~~~~~~~~~

If there is a failure in the middle of the memory space loop,
only some of the memory spaces need to be cleaned up.

At the error handler, idx holds the number of successful
memory spaces mapped.  So rework the handler loop to use the
old idx.

There is a second problem, the memory space loop conditionally
iomaps()/sets the mem_base so it is necessay to initize pci.

Fixes: 719f82d3987a ("ALSA: Add support of AudioScience ASI boards")
Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20200913165230.17166-1-trix@redhat.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>