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/at91sam9g45.h b/include/asm-arm/arch-at91/at91sam9g45.h
index 99c03f7..445f4b2 100644
--- a/include/asm-arm/arch-at91/at91sam9g45.h
+++ b/include/asm-arm/arch-at91/at91sam9g45.h
@@ -147,6 +147,6 @@
 /*
  * Cpu Name
  */
-#define AT91_CPU_NAME	"AT91SAM9G45"
+#define CONFIG_SYS_AT91_CPU_NAME	"AT91SAM9G45"
 
 #endif