Looks like we currently only detect UART on omap36xx, let's also
add support for omap34xx. And let's also fix the SWSUP mode, it should
be SWSUP_SIDLE for omap3, not SWSUP_SIDLE_ACT like for omap4 and later.
Note that we are still booting omap3 for most part without ti-sysc,
so no need to treat this change as a fix.
Tested-by: Keerthy <j-keerthy@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com>