epm-adc: Fix lockdep warnings with key's not in .data

Devices attributes have lockdep keys and so they should exist in
the data section. Failure to do this results in lockdep turning
itself off and warnings such as:

	BUG: key eeb0883c not in .data!

Fix this problem by statically allocating the devices attributes
and hardcoding the names instead of generating them dynamically.

Change-Id: I8db28768b3bdffab21db8c2ea2cfb21f0e4010c1
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>