Revert "x86, ptrace: fix build breakage with gcc 4.7"

This reverts commit 4ed3bb08.

As reported by Sven-Haegar Koch, this patch breaks make headers_check :

   CHECK   include (0 files)
   CHECK   include/asm (54 files)
   /home/haegar/src/2.6.32/linux/usr/include/asm/ptrace.h:5: included file 'linux/linkage.h' is not exported
Signed-off-by: Willy Tarreau <w@1wt.eu>

arch/x86/include/asm/ptrace.h

@@ -2,7 +2,6 @@
 #define _ASM_X86_PTRACE_H
 
 #include <linux/compiler.h>	/* For __user */
-#include <linux/linkage.h>	/* For asmregparm */
 #include <asm/ptrace-abi.h>
 #include <asm/processor-flags.h>
 
@@ -143,8 +142,8 @@ extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
 			 int error_code, int si_code);
 void signal_fault(struct pt_regs *regs, void __user *frame, char *where);
 
-extern asmregparm long syscall_trace_enter(struct pt_regs *);
-extern asmregparm void syscall_trace_leave(struct pt_regs *);
+extern long syscall_trace_enter(struct pt_regs *);
+extern void syscall_trace_leave(struct pt_regs *);
 
 static inline unsigned long regs_return_value(struct pt_regs *regs)
 {