ARM change name of defines for AT91 arm926ejs

Configuration defines should be preceeded with CONFIG_SYS_. Renamed
some at91 specific defines to conform to this naming convention:

AT91_CPU_NAME to CONFIG_SYS_AT91_CPU_NAME
AT91_MAIN_CLOCK to CONFIG_SYS_AT91_MAIN_CLOCK

Signed-off-by: Achim Ehrlich <aehrlich@taskit.de>
diff --git a/include/asm-arm/arch-at91/at91rm9200.h b/include/asm-arm/arch-at91/at91rm9200.h
index 990f5a6..1bee6f2 100644
--- a/include/asm-arm/arch-at91/at91rm9200.h
+++ b/include/asm-arm/arch-at91/at91rm9200.h
@@ -130,6 +130,6 @@
 #define AT91_PMX_CA_NCS7	0x00002000
 #define AT91_PMX_CA_D16_31	0xFFFF0000
 
-#define AT91_CPU_NAME	"AT91RM9200"
+#define CONFIG_SYS_AT91_CPU_NAME	"AT91RM9200"
 
 #endif