drivers/isdn/hisax: fix sparse warning: Should it be static?

Impact: Move declarations to a header file.

Fix this sparse warning:
  drivers/isdn/hisax/callc.c:24:12: warning: symbol 'lli_revision' was not declared. Should it be static?
  drivers/isdn/hisax/config.c:84:12: warning: symbol 'CardType' was not declared. Should it be static?
  drivers/isdn/hisax/config.c:362:5: warning: symbol 'nrcards' was not declared. Should it be static?
  drivers/isdn/hisax/isdnl1.c:21:12: warning: symbol 'l1_revision' was not declared. Should it be static?
  drivers/isdn/hisax/isdnl2.c:22:12: warning: symbol 'l2_revision' was not declared. Should it be static?
  drivers/isdn/hisax/isdnl3.c:22:12: warning: symbol 'l3_revision' was not declared. Should it be static?
  drivers/isdn/hisax/tei.c:23:12: warning: symbol 'tei_revision' was not declared. Should it be static?

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: David S. Miller <davem@davemloft.net>