[PORT FROM R2] mid_pmu: fix klockwork issues

[PORT FROM R2] mid_pmu: fix klockwork issues

BZ: 18375

This patch fixes following klockwork issues:

function 'strncpy' may incorrectly check buffer
boundaries and may overflow buffer 'valcp' of fixed size (5)
linux-2.6/arch/x86/platform/mfld/pmu.c:491 | set_extended_cstate_mode()

function 'strncpy' may incorrectly check buffer
boundaries and may overflow buffer 'valcp' of fixed size (4)
linux-2.6/arch/x86/platform/mfld/pmu.c:578 | set_pmu_driver_status()

Change-Id: Icead563c02b57b122a676c490e8cf134928595a3
Orig-Change-Id: I41a62d195a5155fafde5320fe014bd0bf123514c
Signed-off-by: Sudarshan Ramachandra <sudarshan.n.ramachandra@intel.com>
Reviewed-on: http://android.intel.com:8080/30277
Reviewed-by: Martin, LoicX <loicx.martin@intel.com>
Reviewed-by: Mansoor, Illyas <illyas.mansoor@intel.com>
Tested-by: Martin, LoicX <loicx.martin@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>