[U-Boot] ut dm pch sandbox test failures

[Stephen Warren]

With the latest push to u-boot.git master branch, I'm seeing the 
following failures running test/py on sandbox:

=> ut dm pch_base
Test: dm_test_pch_base: pch.c
/var/lib/jenkins/workspace/u-boot-denx_uboot-master-build/src/u-boot/test/dm/pch.c:20, 
dm_test_pch_base(): 0 == uclass_first_device_err(UCLASS_PCH, &dev): 
Expected 0, got -19
Test: dm_test_pch_base: pch.c (flat tree)
/var/lib/jenkins/workspace/u-boot-denx_uboot-master-build/src/u-boot/test/dm/pch.c:20, 
dm_test_pch_base(): 0 == uclass_first_device_err(UCLASS_PCH, &dev): 
Expected 0, got -19
Failures: 2

=> ut dm pch_ioctl
Test: dm_test_pch_ioctl: pch.c
/var/lib/jenkins/workspace/u-boot-denx_uboot-master-build/src/u-boot/test/dm/pch.c:44, 
dm_test_pch_ioctl(): 0 == uclass_first_device_err(UCLASS_PCH, &dev): 
Expected 0, got -19
Test: dm_test_pch_ioctl: pch.c (flat tree)
/var/lib/jenkins/workspace/u-boot-denx_uboot-master-build/src/u-boot/test/dm/pch.c:44, 
dm_test_pch_ioctl(): 0 == uclass_first_device_err(UCLASS_PCH, &dev): 
Expected 0, got -19
Failures: 2