lib/Kconfig.debug: fix typo in the help text of CONFIG_PANIC_TIMEOUT

There exists duplicated "the" in the help text of CONFIG_PANIC_TIMEOUT,
Remove it.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Xuefeng Li <lixuefeng@loongson.cn>
Link: http://lkml.kernel.org/r/1591103358-32087-2-git-send-email-yangtiezhu@loongson.cn


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>