configs: imx: Make CONFIG_SYS_PROMPT uniform across FSL boards

There is no real benefit in adding the board name into U-boot's prompt.

Use the simple "=> " prompt across FSL boards.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Acked-by: Otavio Salvador <otavio@ossystems.com.br>
diff --git a/include/configs/mx6sabre_common.h b/include/configs/mx6sabre_common.h
index bf6113b..b0bb02c 100644
--- a/include/configs/mx6sabre_common.h
+++ b/include/configs/mx6sabre_common.h
@@ -171,7 +171,7 @@
 #define CONFIG_SYS_LONGHELP
 #define CONFIG_SYS_HUSH_PARSER
 #define CONFIG_SYS_PROMPT_HUSH_PS2     "> "
-#define CONFIG_SYS_PROMPT              "U-Boot > "
+#define CONFIG_SYS_PROMPT              "=> "
 #define CONFIG_AUTO_COMPLETE
 #define CONFIG_SYS_CBSIZE              256