linux-phytec-fsl

README: Add ARC architecture

ARC support was added back in 2013 but I missed updating here

Reported-by: Francois Bedard <fbedard@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>