[MIPS] Excite: disable 64-bit kernel support.

  CC      arch/mips/basler/excite/excite_prom.o
arch/mips/basler/excite/excite_prom.c:136:3: #error 64 bit support not implemented
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -28,7 +28,6 @@ config BASLER_EXCITE
 	select MIPS_RM9122
 	select SYS_HAS_CPU_RM9000
 	select SYS_SUPPORTS_32BIT_KERNEL
-	select SYS_SUPPORTS_64BIT_KERNEL
 	select SYS_SUPPORTS_BIG_ENDIAN
 	select SYS_SUPPORTS_KGDB
 	help