staging: dgap: remove unused code

dgap_sindex() is being only called from dgap_getword() which searches
for either ' ' or '\t' or '\n'. this part of the code with '^' at the
beginning is never used.

Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>