simplify repeating IO sequence

Change-Id: Ice16a6614db2337c43be265eff0ea21699c701b6
Introduce a radeon_read()

Change-Id: I967b3ff5a2479166347335a7b0198c519a047451
Simplify some more

Change-Id: Ia1205b968ee4198dfd877cc34792e06d483db8cc
remove double cummas

Change-Id: I9829a1f765501a9aa46f99c4e456e92b33007b0c