dm: at91: snapper: Move driver model CONFIGs to Kconfig

Remove driver model CONFIGs from the board config headers and use Kconfig
instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/snapper9260_defconfig b/configs/snapper9260_defconfig
index 7055e2a..035146c 100644
--- a/configs/snapper9260_defconfig
+++ b/configs/snapper9260_defconfig
@@ -1,3 +1,6 @@
 CONFIG_SYS_EXTRA_OPTIONS="AT91SAM9260"
 CONFIG_ARM=y
 CONFIG_TARGET_SNAPPER9260=y
+CONFIG_DM=y
+CONFIG_DM_GPIO=y
+CONFIG_DM_SERIAL=y
diff --git a/configs/snapper9g20_defconfig b/configs/snapper9g20_defconfig
index 2faae15..66c44cc 100644
--- a/configs/snapper9g20_defconfig
+++ b/configs/snapper9g20_defconfig
@@ -1,3 +1,6 @@
 CONFIG_SYS_EXTRA_OPTIONS="AT91SAM9G20"
 CONFIG_ARM=y
 CONFIG_TARGET_SNAPPER9260=y
+CONFIG_DM=y
+CONFIG_DM_GPIO=y
+CONFIG_DM_SERIAL=y
diff --git a/include/configs/snapper9260.h b/include/configs/snapper9260.h
index 9fa644f..712f9b7 100644
--- a/include/configs/snapper9260.h
+++ b/include/configs/snapper9260.h
@@ -21,10 +21,6 @@
 #define CONFIG_SYS_AT91_MAIN_CLOCK	18432000 /* External Crystal, in Hz */
 #define CONFIG_SYS_AT91_SLOW_CLOCK	32768
 #define CONFIG_SYS_GENERIC_BOARD
-#define CONFIG_DM
-#define CONFIG_CMD_DM
-#define CONFIG_DM_GPIO
-#define CONFIG_DM_SERIAL
 #define CONFIG_SYS_MALLOC_F_LEN		(1 << 10)
 
 /* CPU */