console: Remove vprintf() optimisation for sandbox

console: Remove vprintf() optimisation for sandbox

If the console is not present, we try to reduce overhead by stopping any
output in vprintf(), before it gets to putc(). This is of dubious merit
in general, but in the case of sandbox it is incorrect since we have a
fallback console which reports errors very early in U-Boot. If this is
defeated U-Boot can hang or exit with no indication of what is wrong.

Remove the optimisation for sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>