openrisc: Fix broken paths to arch/or32

OpenRISC was mainlined as "openrisc", not "or32".
vmlinux.lds is generated from vmlinux.lds.S.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>

arch/openrisc/kernel/entry.S

@@ -240,7 +240,7 @@ handler:							;\
  *	 occured. in fact they never do. if you need them use
  *	 values saved on stack (for SPR_EPC, SPR_ESR) or content
  *       of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE()
- *       in 'arch/or32/kernel/head.S'
+ *       in 'arch/openrisc/kernel/head.S'
  */
 
 /* =====================================================[ exceptions] === */