hw/pl110: Model the PL111 CLCD controller

hw/pl110: Model the PL111 CLCD controller

Model the PL111 CLCD controller. This is a minor variation
on the PL110; the major programmer visible differences are
support for hardware cursor (unimplemented) and two new
pixel formats.

Since syborg_fb.c borrows the pl11x pixel drawing routines,
we also update it to cope with the new slightly larger array
of function pointers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>