sys_rand_get() is used to initialize __stack_chk_guard under
CONFIG_STACK_CANARIES_TLS, but <zephyr/random/random.h> was included
under CONFIG_CURRENT_THREAD_USE_TLS. Builds fail when
STACK_CANARIES_TLS=y and CURRENT_THREAD_USE_TLS=n. Also fix the
mismatched endif comment.
Signed-off-by: Yiren Guo <guoyr_2013@hotmail.com>