usb: phy: snps: Remove emulation sequences

The emulation initialization sequences are not really a feature
of the Synopsys HS PHY and there is already a separate driver for
that used only on emulation platforms. Remove the unused code from
this driver.

Change-Id: I2ea7a060f298010f12a8e282aa004193e0d3a2bb
Signed-off-by: Jack Pham <jackp@codeaurora.org>