The last patch supports several syscalls in linux-record.c, so now
GDB aarch64-linux backend can return these canonicalized syscall numbers
per aarch64 syscall number.

This patch fixes the following fails,

Process record and replay target doesn't support syscall number 59^M
Process record: failed to record execution log.^M
^M
Program stopped.^M
0x00000020000eab28 in pipe () from /lib/aarch64-linux-gnu/libc.so.6^M
(gdb) FAIL: gdb.reverse/pipe-reverse.exp: continue to breakpoint: marker2

Process record and replay target doesn't support syscall number 59^M
Process record: failed to record execution log.^M
^M
Program stopped.^M
0x00000020000eab28 in pipe () from /lib/aarch64-linux-gnu/libc.so.6^M
(gdb) FAIL: gdb.reverse/readv-reverse.exp: continue to breakpoint: marker2

gdb:

2016-02-29  Yao Qi  <yao.qi@linaro.org>

	* aarch64-linux-tdep.c (aarch64_canonicalize_syscall): Support
	eventfd2, eventfd2, dup3, inotify_init1, fallocate and pipe2.
	Return gdb_sys_epoll_create1 instead of gdb_sys_epoll_create
	for aarch64_sys_epoll_create1.