sh: Fix an off-by-1 in FTRACE_SYSCALL_MAX.

This is supposed to be the equivalent of __NR_syscalls, not
__NR_syscalls -1. The x86 code this was based on had simply fallen
out of sync at the time this was implemented. Fix it up now.

As a result, tracing of __NR_perf_counter_open works as advertised.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/ftrace.h

@@ -4,7 +4,7 @@
 #ifdef CONFIG_FUNCTION_TRACER
 
 #define MCOUNT_INSN_SIZE	4 /* sizeof mcount call */
-#define FTRACE_SYSCALL_MAX	(NR_syscalls - 1)
+#define FTRACE_SYSCALL_MAX	NR_syscalls
 
 #ifndef __ASSEMBLY__
 extern void mcount(void);