uml: rename pt_regs general-purpose register file

Before the removal of tt mode, access to a register on the skas-mode side of a
pt_regs struct looked like pt_regs.regs.skas.regs.regs[FOO].  This was bad
enough, but it became pt_regs.regs.regs.regs[FOO] with the removal of the
union from the middle.  To get rid of the run of three "regs", the last field
is renamed to "gp".

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/sys-x86_64/tls.c

@@ -11,7 +11,7 @@ int arch_copy_tls(struct task_struct *t)
 	 * (which is argument 5, child_tid, of clone) so it can be set
 	 * during context switches.
 	 */
-	t->thread.arch.fs = t->thread.regs.regs.regs[R8 / sizeof(long)];
+	t->thread.arch.fs = t->thread.regs.regs.gp[R8 / sizeof(long)];
 
 	return 0;
 }