drivers/edac: mod edac_opt_state_to_string function

Refactored the function edac_op_state_toString() to be edac_op_state_to_string()
for consistent style, and its callers

Signed-off-by: Douglas Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>