usb: dwc3-msm: remove unused/obsolete code

The following features are no longer used. Remove them.

Module param cpu_to_affin previously used cpu notifiers which are
no longer supported. Recent SoCs have had no performance issues
with multi-core IRQ affinity.

Unused DT properties:
- tcsr_base: was only used for configuring top-level configuration
  register to switch between primary/secondary PHY. Unused since
  APQ8084. If needed, tcsr syscon should be used instead of directly
  mapping this register.
- pmic_id_irq: external ID pin is handled completely by extcon
- qcom,ext-hub-reset-gpio: unused on current SoCs
- qcom,disable-host-mode-pm: unused on current SoCs

Remove dwc3_msm_update_ref_clk() as current SoCs have the correct
default register values programmed.

Change-Id: I1bce81234933c6bb8891e1f7606ea04e862ab1f1
Signed-off-by: Jack Pham <jackp@codeaurora.org>