arm: Fix wrong system call number

System call number 78 corresponds to readlinkat.
Where as 78 is mapped to readlink() in syscall.def for
arm.

With this patch, use sys_readlinkat instead of sys_readlink
and update syscall.def to point syscall number 78 to readlinkat()
instead of readlink()
Signed-off-by: Vijaya Kumar K <vijayak@caviumnetworks.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

arch/arm/syscall.def

@@ -52,7 +52,7 @@ flock				32	143	(int fd, unsigned long cmd)
 mkdir				!	39	(const char *name, int mode)
 rmdir				!	40	(const char *name)
 unlink				!	10	(char *pathname)
-readlink			78	85	(const char *path, char *buf, int bufsize)
+readlinkat			78	85	(int fd, const char *path, char *buf, int bufsize)
 umask				166	60	(int mask)
 getgroups			158	205	(int gsize, unsigned int *groups)
 setgroups			159	206	(int gsize, unsigned int *groups)

pie/parasite.c

@@ -289,7 +289,7 @@ static int parasite_get_proc_fd()
 	int ret, fd = -1;
 	char buf[2];
 
-	ret = sys_readlink("/proc/self", buf, sizeof(buf));
+	ret = sys_readlinkat(AT_FDCWD, "/proc/self", buf, sizeof(buf));
 	if (ret < 0 && ret != -ENOENT) {
 		pr_err("Can't readlink /proc/self (%d)\n", ret);
 		return ret;