efi_loader: disk: a helper function to create efi_disk objects from udevice

Add efi_disk_probe() function.
This function creates an efi_disk object for a raw disk device (UCLASS_BLK)
and additional objects for related partitions (UCLASS_PARTITION).

So this function is expected to be called through driver model's "probe"
interface every time one raw disk device is detected and activated.
We assume that partition devices (UCLASS_PARTITION) have been created
when this function is invoked.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index bc518d7..6b245f5 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -14,6 +14,8 @@
 	depends on DM_ETH || !NET
 	depends on !EFI_APP
 	default y if !ARM || SYS_CPU = armv7 || SYS_CPU = armv8
+	select DM_EVENT
+	select EVENT_DYNAMIC
 	select LIB_UUID
 	imply PARTITION_UUIDS
 	select HAVE_BLOCK_DEVICE
@@ -40,6 +42,7 @@
 
 config EFI_SETUP_EARLY
 	bool
+	default y
 
 choice
 	prompt "Store for non-volatile UEFI variables"