usb: dwc3: Fix bare use of unsigned checkpatch warning

Fixes the bare use of unsigned warning from checkpatch.pl in core.c by
changing 'unsigned' to 'unsigned int'.

Signed-off-by: Kushagra Verma <kushagra765@outlook.com>
Link: https://lore.kernel.org/r/HK0PR01MB280160BCA168FA9FE159F02AF8D39@HK0PR01MB2801.apcprd01.prod.exchangelabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>