xtensa: minor compiler warning fix

Fix two compiler warnings complaining about truncating a value on
a 64-bit host, and about declaring an unused variable that is only
used for a specific configuration.
Signed-off-by: NChris Zankel <chris@zankel.net>

arch/xtensa/kernel/entry.S

@@ -1542,7 +1542,7 @@ ENTRY(fast_second_level_miss)
 	 * pteval = ((pmdval - PAGE_OFFSET) & PAGE_MASK) | PAGE_DIRECTORY
 	 */
 
-	movi	a1, -PAGE_OFFSET
+	movi	a1, (-PAGE_OFFSET) & 0xffffffff
 	add	a0, a0, a1		# pmdval - PAGE_OFFSET
 	extui	a1, a0, 0, PAGE_SHIFT	# ... & PAGE_MASK
 	xor	a0, a0, a1

arch/xtensa/kernel/process.c

@@ -190,10 +190,13 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
                 struct task_struct * p, struct pt_regs * regs)
 {
 	struct pt_regs *childregs;
-	struct thread_info *ti;
 	unsigned long tos;
 	int user_mode = user_mode(regs);
 
+#if (XTENSA_HAVE_COPROCESSORS || XTENSA_HAVE_IO_PORTS)
+	struct thread_info *ti;
+#endif
+
 	/* Set up new TSS. */
 	tos = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 	if (user_mode)