usb: core: driver: fix stray tabs in error messages

Commit 8bb54ab5 ("usbcore: add usb_device_driver definition") added
the printk() calls with the error massages spoilt due to the stray tabs
in the middle. Remove these tabs and convert printk() calls to pr_err()
for consistency with the other code, while at it.

Fixes: 8bb54ab5

 ("usbcore: add usb_device_driver definition")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omprussia.ru>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/4beb55c4-eb34-7744-155f-033b8f527e23@omprussia.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>