dm: test: Add tests for the generic PHY uclass

Those tests check:
- the ability for a phy-user to get a phy based on its name or its index
- the ability of a phy device (provider) to manage multiple ports
- the ability to perform operations on the phy (init,deinit,on,off)
- the behavior of the uclass when optional operations are not implemented

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/sandbox_noblk_defconfig b/configs/sandbox_noblk_defconfig
index fb98ab8..26183af 100644
--- a/configs/sandbox_noblk_defconfig
+++ b/configs/sandbox_noblk_defconfig
@@ -174,6 +174,8 @@
 CONFIG_VIDEO_SANDBOX_SDL=y
 CONFIG_FS_CBFS=y
 CONFIG_FS_CRAMFS=y
+CONFIG_PHY=y
+CONFIG_PHY_SANDBOX=y
 CONFIG_CMD_DHRYSTONE=y
 CONFIG_TPM=y
 CONFIG_LZ4=y