Move arm user.h definitions to sys/user.h.

There is no uapi user.h file for arm, it was included by accident.
Move the user struct definition into the file to follow the pattern
used by the other architectures.

Change-Id: Ib9cea0deca551c9268382ddd6de9202fd32ef941

libc/include/sys/user.h

@@ -179,10 +179,48 @@ struct user {
   char u_comm[32];
 };
 
+#elif defined(__arm__)
+
+struct user_fp {
+  struct fp_reg {
+    unsigned int sign1:1;
+    unsigned int unused:15;
+    unsigned int sign2:1;
+    unsigned int exponent:14;
+    unsigned int j:1;
+    unsigned int mantissa1:31;
+    unsigned int mantissa0:32;
+  } fpregs[8];
+  unsigned int fpsr:32;
+  unsigned int fpcr:32;
+  unsigned char ftype[8];
+  unsigned int init_flag;
+};
+struct user{
+  struct pt_regs regs;
+  int u_fpvalid;
+  unsigned long int u_tsize;
+  unsigned long int u_dsize;
+  unsigned long int u_ssize;
+  unsigned long start_code;
+  unsigned long start_stack;
+  long int signal;
+  int reserved;
+  unsigned long u_ar0;
+  unsigned long magic;
+  char u_comm[32];
+  int u_debugreg[8];
+  struct user_fp u_fp;
+  struct user_fp_struct * u_fp0;
+};
+
+#elif defined(__aarch64__)
+
+// There are no user structures for 64 bit arm.
+
 #else
 
-/* arm and aarch64 have uapi user.h headers. */
-#include <asm/user.h>
+#error "Unsupported architecture."
 
 #endif