tty: remove redundant condition checks

Remove redundant condition checks and replace else if with else.

Signed-off-by: Xichao Zhao <zhao.xichao@vivo.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20250905091321.437476-1-zhao.xichao@vivo.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>