staging: agnx: drivers/staging/agnx/agnx.h needs <linux/io.h>

On m68k:
drivers/staging/agnx/agnx.h: In function 'agnx_read32':
drivers/staging/agnx/agnx.h:10: error: implicit declaration of function 'ioread32'
drivers/staging/agnx/agnx.h: In function 'agnx_write32':
drivers/staging/agnx/agnx.h:15: error: implicit declaration of function 'iowrite32'
drivers/staging/agnx/sta.c: In function 'get_sta_power':
drivers/staging/agnx/sta.c:94: error: implicit declaration of function 'memcpy_fromio'
drivers/staging/agnx/sta.c: In function 'set_sta_power':
drivers/staging/agnx/sta.c:103: error: implicit declaration of function 'memcpy_toio'

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>