ARC: cacheflush refactor #3: Unify the {d,i}cache flush leaf helpers
ARC: cacheflush refactor #3: Unify the {d,i}cache flush leaf helpers

With Line length being constant now, we can fold the 2 helpers into 1.
This allows applying any optimizations (forthcoming) to single place.

Signed-off-by: Vineet Gupta <af669d95a4c0de051445d4cafdbb2c5c4a2838be@synopsys.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs