msghdr: change register based size types from unsigned long to kernel_ureg_t

msghdr: change register based size types from unsigned long to kernel_ureg_t

* defs.h (dumpiov_in_msghdr): Change data_size argument type
from unsigned long to kernel_ureg_t.
* msghdr.h (print_struct_msghdr): Likewise.
* msghdr.c (print_struct_msghdr): Likewise.  Cast msghdr.msg_iovlen
and msghdr.msg_controllen to kernel_ureg_t instead of unsigned long.
(decode_msghdr, dumpiov_in_msghdr): Change data_size argument type
from unsigned long to kernel_ureg_t.
(SYS_FUNC(sendmsg)): Pass -1 instead of -1UL as data_size argument
to decode_msghdr.
* mmsghdr.c (print_struct_mmsghdr): Pass (kernel_ureg_t) -1 instead
of -1UL as data_size argument to print_struct_msghdr.
(dumpiov_in_mmsghdr): Cast msghdr.msg_iovlen to kernel_ureg_t instead
of unsigned long.
* syscall.c (dumpio): Pass -1 instead of -1UL as data_size argument
to dumpiov_in_msghdr