MIPS: remove obsolete Kconfig macros

MIPS: remove obsolete Kconfig macros

The support for PB1100, PB1500, and PB1550 got merged into the code for
DB1000 and DB1550 code in v3.7. When that was done the three related
Kconfig symbols were dropped. But not all related Kconfig macros were
removed. Do so now.

Note that the PB1100 code in the Au1100 LCD driver is removed entirely
and not converted to use its current Kconfig macro. That is done because
the macros it uses (PB1100_G_CONTROL, PB1100_G_CONTROL_BL, and
PB1100_G_CONTROL_VDD) are never defined. Actually only one of these was
ever defined (PB1100_G_CONTROL) but that define was removed in v2.6.34.
So, as far as I can tell, this code could have never compiled.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Patchwork: http://patchwork.linux-mips.org/patch/5040/
Acked-by: John Crispin <blogic@openwrt.org>