usb: phy: phy-fsl-usb: Remove some unused functions

Removes some functions that are not used anywhere:
fsl_otg_tick_timer() view_ulpi()

This was partially found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Felipe Balbi <balbi@ti.com>