pccardctl: add array out-of-bounds exception

The following patch fixes an array out-of-bounds exception, which is easily
triggered with Ricoh's Bay8Controller.

Additionally, following improvements are made:
- correct a check for NULL path name
- make lookup tables const
- fix warnings stemming from printf() format strings

Signed-off-by: Robert Varga <nite@hq.alert.sk>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>