USB: Use real HID driver in dde_linux

Before, usb_drv included both the real HID driver and also Linux's early
boot USB driver (BP). The BP drivers have been removed now.

Fixes #440.
Fix default base-nova/etc/specs.conf
Reduce debug messages of UART driver
Remove debug message
Core: Fix registration of CPU exception handler
base-nova: Coding style
Merge remote-tracking branch 'upstream/master'