ARM: Fix missing linux/types.h #inclusion in asm/hardware/iop3xx.h

arch/arm/include/asm/hardware/iop3xx.h needs to include linux/types.h to avoid
the following errors:

In file included from arch/arm/plat-iop/restart.c:10:0:
/data/fs/linux-2.6-fscache/arch/arm/include/asm/hardware/iop3xx.h:239:1: error: unknown type name 'u32'
/data/fs/linux-2.6-fscache/arch/arm/include/asm/hardware/iop3xx.h: In function 'read_tmr0':
/data/fs/linux-2.6-fscache/arch/arm/include/asm/hardware/iop3xx.h:241:2: error: unknown type name 'u32'
/data/fs/linux-2.6-fscache/arch/arm/include/asm/hardware/iop3xx.h: At top level:
/data/fs/linux-2.6-fscache/arch/arm/include/asm/hardware/iop3xx.h:246:31: error: unknown type name 'u32'
...

Signed-off-by: David Howells <dhowells@redhat.com>