usb: xhci: move doorbell array pointer assignment

usb: xhci: move doorbell array pointer assignment

Move the assignment of the doorbell array pointer from xhci_mem_init()
to xhci_init(). The assignment now utilizes the newly introduced
xhci_set_doorbell_ptr() function.

Doorbell Array Offset mask (DBOFF_MASK) is updated to directly specify its
bit range as 31:2, rather than using inverted reserved bits 1:0.
This change simplifies the mask representation, making it more intuitive
and easier to understand.

Remove the "// " prefix from trace messages, as it is unnecessary and
distracting.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250515135621.335595-9-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>