malta: Rename CONFIG_MALTA to CONFIG_TARGET_MALTA

Fixup this last remnant of CONFIG_MALTA.

Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/rtc/mc146818.c b/drivers/rtc/mc146818.c
index 122691b..03ce081 100644
--- a/drivers/rtc/mc146818.c
+++ b/drivers/rtc/mc146818.c
@@ -13,7 +13,7 @@
 #include <dm.h>
 #include <rtc.h>
 
-#if defined(CONFIG_X86) || defined(CONFIG_MALTA)
+#if defined(CONFIG_X86) || defined(CONFIG_TARGET_MALTA)
 #include <asm/io.h>
 #define in8(p) inb(p)
 #define out8(p, v) outb(v, p)