configs/debug: restore DEBUG_INFO=y for overriding

Previously, I failed to realize that Kees' patch [1] has not been merged
into the mainline yet, and dropped DEBUG_INFO=y too eagerly from the
mainline.  As the results, "make debug.config" won't be able to flip
DEBUG_INFO=n from the existing .config.  This should close the gaps of a
few weeks before Kees' patch is there, and work regardless of their
merging status anyway.

Link: https://lore.kernel.org/all/20220125075126.891825-1-keescook@chromium.org/ [1]
Link: https://lkml.kernel.org/r/20220308153524.8618-1-quic_qiancai@quicinc.com


Signed-off-by: Qian Cai <quic_qiancai@quicinc.com>
Reported-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>