vgacon: remove prehistoric macros

These macros:
* CAN_LOAD_EGA_FONTS
* CAN_LOAD_PALETTE
* TRIDENT_GLITCH
* VGA_CAN_DO_64KB
* SLOW_VGA
are either always set or always unset. They come from the linux 2.1
times. And given nobody switched them to some configurable options, I
assume nobody actually uses them.

So remove the macros and leave in place appropriate branches of the
conditional code.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-doc@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>