staging: tidspbridge: delete unused mmu functions

This should get rid of warnings of the type:

warning: passing argument 1 of '' discards qualifiers from pointer target type
 note: expected 'void *' but argument is of type 'const void *'

Signed-off-by: Omar Ramirez Luna <omar.ramirez@copitl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>