ia64: add __NR_umount2 definition

Other architectures commonly use __NR_umount2 for sys_umount,
only ia64 and alpha use __NR_umount here. In order to synchronize
the generated tables, use umount2 like everyone else, and add back
the old name from asm/unistd.h for compatibility.

The __IGNORE_* lines are now all obsolete and can be removed as
a side-effect.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/ia64/kernel/syscalls/syscall.tbl

@@ -29,7 +29,7 @@
 17	common	getpid				sys_getpid
 18	common	getppid				sys_getppid
 19	common	mount				sys_mount
-20	common	umount				sys_umount
+20	common	umount2				sys_umount
 21	common	setuid				sys_setuid
 22	common	getuid				sys_getuid
 23	common	geteuid				sys_geteuid