xhci: Allocate separate command structures for each LPM command

xhci: Allocate separate command structures for each LPM command

Every lpm commmand, both for USB 2 and USB 3 devies used the same
xhci->lpm_command structure to change max exit latency.

xhci->lpm_command is only protected by a hcd->bandwidth mutex, which is
not enoungh as USB 2 and USB 3 devices are behind separate HCDs.

Simplify code and avoid unnecessary locking risks by allocating
separate command structures for each lpm command, just like with
all other commands.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220216095153.1303105-7-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>