usb: xhci: move reserving command ring trb

usb: xhci: move reserving command ring trb

Move the command ring TRB reservation from xhci_mem_init() to xhci_init().

Function xhci_mem_init() is intended for memory allocation,
while xhci_init() is for initialization.

This split allows xhci_init() to be reused when resuming from S4
suspend-to-disk.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260402131342.2628648-8-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>