alpha: update syscall macro definitions

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.

For shmat, alpha uses the osf_shmat name, we can do the same thing
here, which means we don't have to add an entry in the __IGNORE
list now that shmat is mandatory everywhere

alarm, creat, pause, time, and utime are optional everywhere
these days, no need to list them here any more.

I considered also adding the regular versions of the get*id system
calls that have different names and calling conventions on alpha,
which would further help unify the syscall ABI, but for now
I decided against that.

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

arch/alpha/kernel/syscalls/syscall.tbl

@@ -29,7 +29,7 @@
 19	common	lseek				sys_lseek
 20	common	getxpid				sys_getxpid
 21	common	osf_mount			sys_osf_mount
-22	common	umount				sys_umount
+22	common	umount2				sys_umount
 23	common	setuid				sys_setuid
 24	common	getxuid				sys_getxuid
 25	common	exec_with_loader		sys_ni_syscall
@@ -183,7 +183,7 @@
 206	common	semop				sys_semop
 207	common	osf_utsname			sys_osf_utsname
 208	common	lchown				sys_lchown
-209	common	osf_shmat			sys_shmat
+209	common	shmat				sys_shmat
 210	common	shmctl				sys_shmctl
 211	common	shmdt				sys_shmdt
 212	common	shmget				sys_shmget