arch/mips: change duplicated word in NUMA help text

Fix wording in NUMA help text.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/Kconfig

@@ -2676,7 +2676,7 @@ config NUMA
 	  Say Y to compile the kernel to support NUMA (Non-Uniform Memory
 	  Access).  This option improves performance on systems with more
 	  than two nodes; on two node systems it is generally better to
-	  leave it disabled; on single node systems disable this option
+	  leave it disabled; on single node systems leave this option
 	  disabled.
 
 config SYS_SUPPORTS_NUMA