[ARM] Fix iop13xx build error

[ARM] Fix iop13xx build error

  CC      arch/arm/mach-iop13xx/setup.o
arch/arm/mach-iop13xx/setup.c: In function 'iq8134x_probe_flash_size':
arch/arm/mach-iop13xx/setup.c:210: warning: implicit declaration of function 'ioremap'
arch/arm/mach-iop13xx/setup.c:210: warning: initialization makes pointer from integer without a cast
arch/arm/mach-iop13xx/setup.c:218: warning: implicit declaration of function 'writew'
arch/arm/mach-iop13xx/setup.c:222: warning: implicit declaration of function 'readb'
arch/arm/mach-iop13xx/setup.c:231: warning: implicit declaration of function 'iounmap'
  LD      .tmp_vmlinux1
arch/arm/mach-iop13xx/built-in.o: In function `iop13xx_platform_init':
iq81340mc.c:(.init.text+0x150): undefined reference to `ioremap'
iq81340mc.c:(.init.text+0x21c): undefined reference to `writew'
iq81340mc.c:(.init.text+0x24c): undefined reference to `writew'
iq81340mc.c:(.init.text+0x254): undefined reference to `iounmap'
iq81340mc.c:(.init.text+0x2c4): undefined reference to `readb'
iq81340mc.c:(.init.text+0x2e8): undefined reference to `readb'

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>