usb: chipidea: udc: fix misuse of REGS_SHARED and PULLUP_ON_VBUS flags

CI_HDRC_REGS_SHARED stands for the controller registers is shared
with other USB drivers, if all USB drivers are at chipidea/, it doesn't
needed to be set.
CI_HDRC_PULLUP_ON_VBUS stands for pullup dp when the vbus is on. This
flag doesn't need to be set if the vbus is always on for gadget
since dp has always pulled up after the gadget has initialized.

So, the current code seems to misuse this two flags.
- When the gadget initializes, the controller doesn't need to run if
it depends on vbus (CI_HDRC_PULLUP_ON_VBUS), it does not relate to
shared register.
- When the gadget starts (load one gadget module), the controller
can run if vbus is on (CI_HDRC_PULLUP_ON_VBUS), it also does not
relate to shared register.

Tested-by: Marek Vasut <marex@denx.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>