unix: update syscall numbers to 4.10 kernel

The syscall numbers for Linux were out of date, so with the release of
the 4.10 kernel, now seemed like a reasonable time to update them. Note
that this change is mostly additive except that it removes some invalid
syscalls for arm, and it removes all constants that refer to either the
syscall base or total number of syscalls. Previous versions had only
removed some of them.

The updated syscall numbers were pulled directly from a header build
of the 4.10 kernel. This required some minor adjustements to the sysnum
generating perl script and is why the comments at the tops of the
generated files look slightly different. I could include the script I
used to do this, but right now it cannot generate the zerrors and ztypes
files.

Change-Id: Id94b967eb917f8f87500f818f2e494df9bccf2e0
Reviewed-on: https://go-review.googlesource.com/37570
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/zsysnum_linux_arm64.go

@@ -1,4 +1,4 @@
-// mksysnum_linux.pl /usr/include/asm-generic/unistd.h
+// mksysnum_linux.pl -Ilinux/usr/include -m64 linux/usr/include/asm/unistd.h
 // MACHINE GENERATED BY THE ABOVE COMMAND; DO NOT EDIT
 
 // +build arm64,linux
@@ -269,4 +269,17 @@ const (
 	SYS_SCHED_GETATTR          = 275
 	SYS_RENAMEAT2              = 276
 	SYS_SECCOMP                = 277
+	SYS_GETRANDOM              = 278
+	SYS_MEMFD_CREATE           = 279
+	SYS_BPF                    = 280
+	SYS_EXECVEAT               = 281
+	SYS_USERFAULTFD            = 282
+	SYS_MEMBARRIER             = 283
+	SYS_MLOCK2                 = 284
+	SYS_COPY_FILE_RANGE        = 285
+	SYS_PREADV2                = 286
+	SYS_PWRITEV2               = 287
+	SYS_PKEY_MPROTECT          = 288
+	SYS_PKEY_ALLOC             = 289
+	SYS_PKEY_FREE              = 290
 )