xtensa: drop unneeded headers from coprocessor.S

A bunch of irrelevant headers is included into coprocessor.S. Remove
them and add necessary asm/regs.h.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/kernel/coprocessor.S

@@ -15,17 +15,9 @@
 #include <linux/linkage.h>
 #include <asm/asm-offsets.h>
 #include <asm/asmmacro.h>
-#include <asm/processor.h>
 #include <asm/coprocessor.h>
-#include <asm/thread_info.h>
-#include <asm/asm-uaccess.h>
-#include <asm/unistd.h>
-#include <asm/ptrace.h>
 #include <asm/current.h>
-#include <asm/pgtable.h>
-#include <asm/page.h>
-#include <asm/signal.h>
-#include <asm/tlbflush.h>
+#include <asm/regs.h>
 
 #if XTENSA_HAVE_COPROCESSORS