board_f: explicitly disable console on early boot

board_f: explicitly disable console on early boot

If U-Boot build with DEBUG enabled/defined the first call of "debug"
function (that dumps data to any available console) will happen before
zeroing of initial "gd" in init call "zero_global_data" in
"init_sequence_f".

And if stack was not filled with zeros chances are high that
"gd->have_console" won't be 0. In its turn it will cause attempt to
output things to non-initialized yet serial console.

So for safety and predictability we set "gd->have_console = 0".

Signed-off-by: Alexey Brodkin <[email protected]>
Cc: Mischa Jonker <[email protected]>
Cc: Wolfgang Denk <[email protected]>
Cc: Simon Glass <[email protected]>
Acked-by: Simon Glass <[email protected]>