Revert "MIPS: Jz4740: Add qi_lb60 board support"

The files board/qi/qi_lb60/qi_lb60.c and include/configs/qi_lb60.h were
licensed under the GPL v3 or later, and not v2 or later.  As this is
incompatible with the project, revert this board support until the
responsible parties are available to re-license (if so desired) under
GPL v2.

Signed-off-by: Tom Rini <trini@ti.com>