Don't use __u64/__u32 in <sys/user.h>.

The typedefs for __u64 and __u32 aren't in scope in this file, so
switch fields declared with these to use the matching underlying type.

Bug: http://b/28178111
Change-Id: Id4eec1f7dc81d77e78043227c15e621debe3a48a
diff --git a/libc/include/sys/user.h b/libc/include/sys/user.h
index 13fecf9..5601b02 100644
--- a/libc/include/sys/user.h
+++ b/libc/include/sys/user.h
@@ -109,13 +109,13 @@
   unsigned short swd;
   unsigned short ftw;
   unsigned short fop;
-  __u64 rip;
-  __u64 rdp;
-  __u32 mxcsr;
-  __u32 mxcr_mask;
-  __u32 st_space[32];
-  __u32 xmm_space[64];
-  __u32 padding[24];
+  unsigned long rip;
+  unsigned long rdp;
+  unsigned int mxcsr;
+  unsigned int mxcr_mask;
+  unsigned int st_space[32];
+  unsigned int xmm_space[64];
+  unsigned int padding[24];
 };
 struct user_regs_struct {
   unsigned long r15;