staging: dgnc: driver.h: changes a struct board_t var's type and marker for sparse

This patch changes the board_t->re_map_membase variable
type and marker.

It removes these warnings found in the neo.c,
driver.c and cls.c files:

warning: incorrect type in argument 1 (different address spaces)
  expected void const volatile [noderef] <asn:2>*addr
  got unsigned char volatile *<noident>
warning: incorrect type in argument 2 (different address spaces)
  expected void volatile [noderef] <asn:2>*addr
  got unsigned char volatile *<noident>

The variables passed to readb and writeb need to
be of type u8 with a __iomem marker. These warnings
were popping up everytime the readb and writeb
functions were called with a
board_t->re_map_membase variable.

The change made to the driver.h file adds the marker
and changes the variable type.

Signed-off-by: Lidza Louina <lidza.louina@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>