At present there is only one control for this and it is used for both SPL
and TPL. But SPL might have a lot more space than TPL so the extra cost of
a full printf() might be acceptable.

Split the option into two, providing separate SPL and TPL controls. The
TPL setting defaults to the same as SPL.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>