Revert "ARCv2: spinlock/rwlock/atomics: reduce 1 instruction in exponential backoff"

This reverts commit 10971638.

The issue was fixed in hardware in HS2.1C release and there are no known
external users of affected RTL - so revert thw whole delayed retry
series !

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