sandbox: Move CONFIG_VIDEO_SANDBOX_SDL to Kconfig

Move this option to Kconfig. This is quite simple as only sandbox uses the
driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index caa7336..65184c8 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -1,6 +1,7 @@
 CONFIG_SYS_MALLOC_F_LEN=0x2000
 CONFIG_PCI=y
 CONFIG_DEFAULT_DEVICE_TREE="sandbox"
+CONFIG_DM_PCI_COMPAT=y
 CONFIG_FIT=y
 CONFIG_FIT_VERBOSE=y
 CONFIG_FIT_SIGNATURE=y
@@ -51,7 +52,6 @@
 CONFIG_SPI_FLASH_WINBOND=y
 CONFIG_DM_ETH=y
 CONFIG_DM_PCI=y
-CONFIG_DM_PCI_COMPAT=y
 CONFIG_PCI_SANDBOX=y
 CONFIG_PINCTRL=y
 CONFIG_PINCONF=y
@@ -76,6 +76,7 @@
 CONFIG_USB_STORAGE=y
 CONFIG_USB_KEYBOARD=y
 CONFIG_SYS_USB_EVENT_POLL=y
+CONFIG_VIDEO_SANDBOX_SDL=y
 CONFIG_CMD_DHRYSTONE=y
 CONFIG_TPM=y
 CONFIG_LZ4=y