checksyscalls: fix "here document" handling

"echo" doesn't read from stdin, therefore the checksyscalls script didn't
warn about not implemented system calls anymore since 29dc54c6
("checksyscalls: Use arch/x86/syscalls/syscall_32.tbl as source").

Use "cat" instead of "echo" which handles this correctly.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checksyscalls.sh

@@ -200,7 +200,7 @@ EOF
 syscall_list() {
     grep '^[0-9]' "$1" | sort -n | (
 	while read nr abi name entry ; do
-	    echo <<EOF
+	    cat <<EOF
 #if !defined(__NR_${name}) && !defined(__IGNORE_${name})
 #warning syscall ${name} not implemented
 #endif