powerpc: remove orphan systbl_chk.sh

arch/powerpc/kernel/systbl_chk.sh has not been referenced since commit
ab66dcc7 ("powerpc: generate uapi header and system call table
files"). Remove it.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220929032120.3592593-1-npiggin@gmail.com

arch/powerpc/kernel/systbl_chk.sh

-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0-or-later
-#
-# Just process the CPP output from systbl_chk.c and complain
-# if anything is out of order.
-#
-# Copyright © 2008 IBM Corporation
-#
-
-awk	'BEGIN { num = -1; }	# Ignore the beginning of the file
-	/^#/ { next; }
-	/^[ \t]*$/ { next; }
-	/^START_TABLE/ { num = 0; next; }
-	/^END_TABLE/ {
-		if (num != $2) {
-			printf "Error: NR_syscalls (%s) is not one more than the last syscall (%s)\n",
-				$2, num - 1;
-			exit(1);
-		}
-		num = -1;	# Ignore the rest of the file
-	}
-	{
-		if (num == -1) next;
-		if (($1 != -1) && ($1 != num)) {
-			printf "Error: Syscall %s out of order (expected %s)\n",
-				$1, num;
-			exit(1);
-		};
-		num++;
-	}' "$1"