The Extended Management Interface (EMI) registers are accessed by first
writing the EMI register offset to the EMI_ADDR regiter and then either
reading or writing the data to/from the EMI_DATA register.  Add helper
functions for performing these steps and convert existing EMI register
accesses accordingly.
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>