x86/syscalls: Remove bash-isms in syscall table generator

Signed-off-by: Sylvain BERTRAND <sylvain.bertrand@gmail.com>
Link: http://lkml.kernel.org/r/20160929162234.GA29592@freedomSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/entry/syscalls/syscalltbl.sh

@@ -10,8 +10,11 @@ syscall_macro() {
 
     # Entry can be either just a function name or "function/qualifier"
     real_entry="${entry%%/*}"
-    qualifier="${entry:${#real_entry}}"		# Strip the function name
-    qualifier="${qualifier:1}"			# Strip the slash, if any
+    if [ "$entry" = "$real_entry" ]; then
+        qualifier=
+    else
+        qualifier=${entry#*/}
+    fi
 
     echo "__SYSCALL_${abi}($nr, $real_entry, $qualifier)"
 }
@@ -22,7 +25,7 @@ emit() {
     entry="$3"
     compat="$4"
 
-    if [ "$abi" == "64" -a -n "$compat" ]; then
+    if [ "$abi" = "64" -a -n "$compat" ]; then
 	echo "a compat entry for a 64-bit syscall makes no sense" >&2
 	exit 1
     fi
@@ -45,17 +48,17 @@ emit() {
 grep '^[0-9]' "$in" | sort -n | (
     while read nr abi name entry compat; do
 	abi=`echo "$abi" | tr '[a-z]' '[A-Z]'`
-	if [ "$abi" == "COMMON" -o "$abi" == "64" ]; then
+	if [ "$abi" = "COMMON" -o "$abi" = "64" ]; then
 	    # COMMON is the same as 64, except that we don't expect X32
 	    # programs to use it.  Our expectation has nothing to do with
 	    # any generated code, so treat them the same.
 	    emit 64 "$nr" "$entry" "$compat"
-	elif [ "$abi" == "X32" ]; then
+	elif [ "$abi" = "X32" ]; then
 	    # X32 is equivalent to 64 on an X32-compatible kernel.
 	    echo "#ifdef CONFIG_X86_X32_ABI"
 	    emit 64 "$nr" "$entry" "$compat"
 	    echo "#endif"
-	elif [ "$abi" == "I386" ]; then
+	elif [ "$abi" = "I386" ]; then
 	    emit "$abi" "$nr" "$entry" "$compat"
 	else
 	    echo "Unknown abi $abi" >&2