staging: sm750fb: sm750_help.h: spacing fix

Remove unnecessary space in sm750_help.h to fix the following
checkpatch.pl error:
drivers/staging/sm750fb/sm750_help.h:46: space prohibited after that '~' (ctx:ExW)

Signed-off-by: Mike Rapoport <mike.rapoport@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>