kernel_htc_m7: Allow compass to work. Ported from Peter Hofinger's work in the AICP project.
AICP references: http://gerrit.aicp-rom.com/#/c/1837/ and http://gerrit.aicp-rom.com/#/c/1838/

Change-Id: I23bac4b937c1f4f52d34c27f88afd7cdb92fe9f4