warp7: Switch to DM Serial

This commit switches to DM SERIAL for warp7 and warp7_bl33 defconfigs.

Signed-off-by: Pierre-Jean Texier <pjtexier@koncepto.io>
Signed-off-by: Joris Offouga <offougajoris@gmail.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/configs/warp7_defconfig b/configs/warp7_defconfig
index 28aa06f..ae424ab 100644
--- a/configs/warp7_defconfig
+++ b/configs/warp7_defconfig
@@ -47,6 +47,8 @@
 CONFIG_DM_REGULATOR_PFUZE100=y
 CONFIG_DM_REGULATOR_FIXED=y
 CONFIG_DM_REGULATOR_GPIO=y
+CONFIG_SPECIFY_CONSOLE_INDEX=y
+CONFIG_DM_SERIAL=y
 CONFIG_OPTEE=y
 CONFIG_USB=y
 CONFIG_USB_EHCI_HCD=y