phy: msm: usb: Clean up debugfs directory on probe failure

Currently we are not cleaning up the already created debugfs
entry for msm_otg if the msm_otg_probe fails. On the subsequent
probe, fresh debugfs entry is not created for the new msm_otg
since the older one already exists, leading to incorrect access.
Fix this by cleaning up the existing debugfs entry if the probe
fails.

Change-Id: I442f06711dec139c16736a8bc7246d02ce1ab999
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>