arm: omap4: Disable USB_TTY and related options

The usbtty functionality is not currently used on these two platforms,
disable it.

Cc: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20210708014348.4010-1-trini@konsulko.com