usb: ehci: Add snapshot of EHCI msm driver

This change adds support for EHCI compliant HSUSB Host
Controller. This driver depends on OTG driver for PHY
initialization, clock management and powering up VBUS.

This snapshot is taken as of msm-3.18 'commit 4a06b0168aeb ("ANDROID:
sdcardfs: Make WARN_RATELIMIT to pr_debug")'.

This change also fixes the coding style and compilation issues.

Change-Id: I5b4b399453a069a8494b2832ebe04a22c0cf8e2a
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>