staging: dgap: Fix mismatch in function argument types

This patch fixes the following error reported by sparse:
drivers/staging/dgap/dgap.c:4428:13: error: symbol 'dgap_do_fep_load' redeclared with different type (originally declared at drivers/staging/dgap/dgap.c:215) - incompatible argument 2 (different address spaces)

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Pablo Neira Ayuso <pablo@gnumonks.org>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>