Remove HAVE_STRUCT_TCB_EXT_ARG, ext_arg, and u_lrval

Remove HAVE_STRUCT_TCB_EXT_ARG, ext_arg, and u_lrval

After transition from long to kernel_ulong_t these fields
are no longer needed.

* defs.h (HAVE_STRUCT_TCB_EXT_ARG): Remove.
(struct tcb) [HAVE_STRUCT_TCB_EXT_ARG]: Remove.
[HAVE_STRUCT_TCB_EXT_ARG]: Remove.
(RVAL_MASK): Update.
* io.c (print_lld_from_low_high_val): Check
[SIZEOF_KERNEL_LONG_T > SIZEOF_LONG]
instead of [HAVE_STRUCT_TCB_EXT_ARG].
Use u_arg instead of ext_arg.
* linux/mips/get_error.c (get_error) [LINUX_MIPSN32]: Remove.
* linux/mips/get_syscall_args.c (get_syscall_args) [LINUX_MIPSN32]:
Remove.
[LINUX_MIPSN64]: Extend to [LINUX_MIPSN32].
* linux/x86_64/get_error.c (get_error) [X32]: Remove.
* linux/x86_64/get_syscall_args.c (get_syscall_args) [X32]: Remove.
* lseek.c: Check [SIZEOF_KERNEL_LONG_T > SIZEOF_LONG]
instead of [HAVE_STRUCT_TCB_EXT_ARG].
[SIZEOF_KERNEL_LONG_T > SIZEOF_LONG] (SYS_FUNC(lseek)): Use u_arg
instead of ext_arg.  Use RVAL_UDECIMAL instead of RVAL_LUDECIMAL.
* mem.c (SYS_FUNC(mmap)): Pass offset syscall argument directly
to print_mmap.
* syscall.c (trace_syscall_exiting) [HAVE_STRUCT_TCB_EXT_ARG]: Remove.
* times.c (SYS_FUNC(times)): Use RVAL_UDECIMAL instead
of RVAL_LUDECIMAL.
* util.c (getllval): Check [SIZEOF_KERNEL_LONG_T > SIZEOF_LONG]
instead of [HAVE_STRUCT_TCB_EXT_ARG].  Use u_arg instead of ext_arg.