build: include ptrace.h after regs.h

Restore the order of including <sys/reg.h> and <linux/ptrace.h>
headers that was inadvertently changed by commit v4.9-280-g5503dd2.

This should fix build on platforms like m68k where some constants
are defined simultaneously as enums by <sys/reg.h> and as macros
by <asm/ptrace.h>.

* process.c: Include "ptrace.h" after "regs.h".
* signal.c: Likewise.
* syscall.c: Likewise.
* util.c: Likewise.

process.c

@@ -42,12 +42,11 @@
 
 #include "xlat/nt_descriptor_types.h"
 
+#include "regs.h"
 #include "ptrace.h"
 #include "xlat/ptrace_cmds.h"
 #include "xlat/ptrace_setoptions_flags.h"
 
-#include "regs.h"
-
 #define uoff(member)	offsetof(struct user, member)
 #define XLAT_UOFF(member)	{ uoff(member), "offsetof(struct user, " #member ")" }
 

signal.c

@@ -34,8 +34,8 @@
 #include "defs.h"
 #include <fcntl.h>
 
-#include "ptrace.h"
 #include "regs.h"
+#include "ptrace.h"
 
 #if defined(SPARC) || defined(SPARC64) || defined(MIPS)
 typedef struct {

syscall.c

@@ -37,6 +37,7 @@
 /* for struct iovec */
 #include <sys/uio.h>
 
+#include "regs.h"
 #include "ptrace.h"
 
 #if defined(SPARC64)
@@ -46,8 +47,6 @@
 # define PTRACE_SETREGS PTRACE_SETREGS64
 #endif
 
-#include "regs.h"
-
 #if defined SPARC64
 # include <asm/psrcompat.h>
 #elif defined SPARC

util.c

@@ -39,8 +39,8 @@
 #endif
 #include <sys/uio.h>
 
-#include "ptrace.h"
 #include "regs.h"
+#include "ptrace.h"
 
 int
 string_to_uint(const char *str)