[console] Try to avoid problems caused by keycode 86

The "us" keyboard layout contains a mapping for keycode 86 (which
seems not to correspond to any physical key on many US keyboards) to
the ASCII character '<'.  This mapping causes conflicts with the
mapping for keycode 51, which also maps (with shift) to '<'.

Change the keyboard mapping generator to choose the lowest keycode for
each ASCII character as indicating the relevant mapping to use, on the
basis that a lower keycode roughly indicates a "more normal" key.  On
a German keyboard, which has keys for both keycode 51 and keycode 86
present, this causes '<' to be remapped to ';', which is a closer
match to typical user expectations.

Reported-by: Sven Dreyer <sven@dreyer-net.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/hci/keymap/keymap_mt.c

@@ -17,5 +17,4 @@ struct key_mapping mt_mapping[] __keymap = {
 	{ 0x40, 0x22 },	/* '@' => '"' */
 	{ 0x5c, 0x23 },	/* '\\' => '#' */
 	{ 0x7c, 0x7e },	/* '|' => '~' */
-	{ 0x7f, 0x08 },	/* 0x7f => Ctrl-H */
 };