usb: dwc3: core: balance phy init and exit

After we start to do core soft reset while usb role switch,
the phy init is invoked at every switch to device mode, but
its counter part de-init is missing, this causes the actual
phy init can not be done when we really want to re-init phy
like system resume, because the counter maintained by phy
core is not 0. considering phy init is actually redundant for
role switch, so move out the phy init from core soft reset to
dwc3 core init where is the only place required.

Fixes: f88359e1

 ("usb: dwc3: core: Do core softreset when switch mode")
Cc: <stable@vger.kernel.org>
Tested-by: faqiang.zhu <faqiang.zhu@nxp.com>
Tested-by: John Stultz <john.stultz@linaro.org> #HiKey960
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Li Jun <jun.li@nxp.com>
Link: https://lore.kernel.org/r/1631068099-13559-1-git-send-email-jun.li@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>