configs: am335x_evm: Do not disable DM_USB in SPL

DM_USB is now supported in the SPL. Do not undef it
Besides to support DM_USB in SPL, one now has to use SPL_DM_USB

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/include/configs/am335x_evm.h b/include/configs/am335x_evm.h
index 5d5b09b..3bd96b9 100644
--- a/include/configs/am335x_evm.h
+++ b/include/configs/am335x_evm.h
@@ -253,7 +253,6 @@
 #ifdef CONFIG_SPL_BUILD
 #undef CONFIG_DM_MMC
 #undef CONFIG_TIMER
-#undef CONFIG_DM_USB
 #endif
 
 #if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_USB_ETHER)