commit 61fb4bfc upstream.

Despite the switch to right UART driver (prev patch), serial console
still doesn't work due to missing CONFIG_SERIAL_OF_PLATFORM

Also fix the default cmdline in DT to not refer to out-of-tree
ARC framebuffer driver for console.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Francois Bedard <Francois.Bedard@synopsys.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>