atstk100x: switch to common cfi driver

This patch removes the board implemenatation for flash driver which can now
safely switched to the common cfi driver.

Compile tested for all atstk100x boards, runtime tested on atstk1002.

Signed-off-by: Andreas Bießmann <biessmann@corscience.de>
diff --git a/include/configs/atstk1003.h b/include/configs/atstk1003.h
index a77d52e..c5e357f 100644
--- a/include/configs/atstk1003.h
+++ b/include/configs/atstk1003.h
@@ -32,8 +32,6 @@
 #define CONFIG_ATSTK1003
 #define CONFIG_ATSTK1000
 
-#define CONFIG_ATSTK1000_EXT_FLASH
-
 /*
  * Timer clock frequency. We're using the CPU-internal COUNT register
  * for this, so this is equivalent to the CPU core clock frequency
@@ -144,11 +142,8 @@
 
 #define CONFIG_NR_DRAM_BANKS		1
 
-/* External flash on STK1000 */
-#if 0
-#define CONFIG_SYS_FLASH_CFI			1
-#define CONFIG_FLASH_CFI_DRIVER		1
-#endif
+#define CONFIG_SYS_FLASH_CFI
+#define CONFIG_FLASH_CFI_DRIVER
 
 #define CONFIG_SYS_FLASH_BASE			0x00000000
 #define CONFIG_SYS_FLASH_SIZE			0x800000