usb: chipidea: core: convert ci_role_switch to local variable

usb: chipidea: core: convert ci_role_switch to local variable

When a system contains multiple USB controllers, the global ci_role_switch
variable may be overwritten by subsequent driver initialization code.

This can cause issues in the following cases:
 - The 2nd ci_hdrc_probe() sees ci_role_switch.fwnode as non-NULL even
   though the "usb-role-switch" property is not present for the controller.
 - When the ci_hdrc device is unbound and bound again, ci_role_switch
   fwnode will not be reassigned, and the old value will be used instead.

Convert ci_role_switch to a local variable to fix these issues.

Fixes: 05559f10ed79 ("usb: chipidea: add role switch class support")
Cc: stable <stable@kernel.org>
Acked-by: Peter Chen <peter.chen@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://patch.msgid.link/20260427075755.3611217-1-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>