xhci: Fix sleeping with spin_lock_irq() held in ASmedia 1042A workaround

xhci: Fix sleeping with spin_lock_irq() held in ASmedia 1042A workaround

BugLink: http://bugs.launchpad.net/bugs/1723145
commit 4ec1cd3eeeee7ccc35681270da028dbc29ca7bbd upstream.

The flow control workaround for ASM1042A xHC hosts sleeps between
register polling. The workaround gets called in several places, among
them with spin_lock_irq() held when xHC host is resumed or hoplug removed.

This was noticed as kernel panics at resume on a Dell XPS15 9550 with
TB16 thunderbolt dock.

Avoid sleeping with spin_lock_irq() held, use udelay() instead

The original workaround was added to 4.9 and 4.12 stable releases,
this patch needs to be applied to those as well.

Fixes: 9da5a1092b13 ("xhci: Bad Ethernet performance plugged in ASM1042A host")
Reported-by: Jose Marino <marinoj@nso.edu>
Tested-by: Jose Marino <marinoj@nso.edu>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>