ARM: dts: Remove unnecessary idle flags for omap5 uart3

Looks like I accidentally left some extra flags for uart3 to
not idle it. This happened as I generated the data from a
running system where these flags are set dynamically on boot
by omap_hwmod_setup_earlycon_flags() if earlycon is enabled.

We can just remove them.

Fixes: 4c387984

 ("ARM: dts: omap5: Add l4 interconnect hierarchy and ti-sysc data")
Signed-off-by: Tony Lindgren <tony@atomide.com>