staging/atomisp: add PCI dependency

Without CONFIG_PCI, config space reads never return any data,
leading to undefined behavior that gcc warns about:

platform/intel-mid/intel_mid_pcihelpers.c: In function 'intel_mid_msgbus_read32_raw':
platform/intel-mid/intel_mid_pcihelpers.c:66:9: error: 'data' is used uninitialized in this function [-Werror=uninitialized]
platform/intel-mid/intel_mid_pcihelpers.c: In function 'intel_mid_msgbus_read32_raw_ext':
platform/intel-mid/intel_mid_pcihelpers.c:84:9: error: 'data' is used uninitialized in this function [-Werror=uninitialized]
platform/intel-mid/intel_mid_pcihelpers.c: In function 'intel_mid_msgbus_read32':
platform/intel-mid/intel_mid_pcihelpers.c:137:9: error: 'data' is used uninitialized in this function [-Werror=uninitialized]

With a dependency on CONFIG_PCI, we don't get this warning. This seems
safe as PCI config space accessors should always return something
when PCI is enabled.

Fixes: a49d2536 ("staging/atomisp: Add support for the Intel IPU v2")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>