[lib][debug] fix build error when dprintf() is disabled
[lib][debug] fix build error when dprintf() is disabled

sndnvaps/lk,ErikCorryGoogle/lk,travisg/lk,littlekernel/lk,hollanderic/lkstuff,travisg/lk,travisg/lk,sndnvaps/lk,hollanderic/lkstuff,sndnvaps/lk,hollanderic/lkstuff,hollanderic/lkstuff,littlekernel/lk,littlekernel/lk,ErikCorryGoogle/lk,ErikCorryGoogle/lk,minglun-tsai/lk,minglun-tsai/lk,ErikCorryGoogle/lk,travisg/lk,sndnvaps/lk,littlekernel/lk,minglun-tsai/lk,minglun-tsai/lk,sndnvaps/lk