sh: Fix up SH-X3 general exception handler build.

With the recent entry.S refactoring, the SH-X3 path had a mov.l for a
register to register copy, resulting in:

  AS      arch/sh/kernel/cpu/sh4/../sh3/entry.o
arch/sh/kernel/cpu/sh4/../sh3/entry.S: Assembler messages:
arch/sh/kernel/cpu/sh4/../sh3/entry.S:366: Error: invalid operands for opcode
make[3]: *** [arch/sh/kernel/cpu/sh4/../sh3/entry.o] Error 1

Switch it over to a mov to fix it up.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/kernel/cpu/sh3/entry.S

@@ -363,7 +363,7 @@ general_exception:
 
 	! Save registers / Switch to bank 0
 	bsr	save_regs	! needs original pr value in k3
-	 mov.l	k4, k2		! keep vector in k2
+	 mov	k4, k2		! keep vector in k2
 
 	bra	handle_exception_special
 	 nop