arc: Add defines for many more useful auxiliary registers

The ARC CPUs have several other features controlled by aux registers.
Specifically, I will be needing ones for i-cache, d-cache and various
BUILD registers that indicate which features are present.

Change-Id: If15a330f4ea5aa519655f88526fbb5f600d7cc0b
Signed-off-by: Chuck Jordan <cjordan@synopsys.com>