[MIPS] Atlas: Fix building the RTC driver

Atlas maps its RTC chip in the host mmio space rather than using the
"traditional" location in the PCI/ISA port space.  A change that has
happened to the generic RTC header requires to define ARCH_RTC_LOCATION
now.
Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/mach-atlas/mc146818rtc.h

@@ -28,6 +28,8 @@
 #include <asm/mips-boards/atlas.h>
 #include <asm/mips-boards/atlasint.h>
 
+#define ARCH_RTC_LOCATION
+
 #define RTC_PORT(x)	(ATLAS_RTC_ADR_REG + (x) * 8)
 #define RTC_IO_EXTENT	0x100
 #define RTC_IOMAPPED	0