SFI: fix compiler warnings

drivers/sfi/sfi_core.c:164:26: warning: no previous prototype for ‘sfi_map_table’ [-Wmissing-prototypes]
drivers/sfi/sfi_core.c:192:6: warning: no previous prototype for ‘sfi_unmap_table’ [-Wmissing-prototypes]

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
cpufreq: Add SFI based cpufreq driver support

This adds the SFI based cpu freq driver for some of the Intel's
Silvermont based Atom architectures like Z34xx and Z35xx.

Signed-off-by: Rudramuni, Vishwesh M <vishwesh.m.rudramuni@intel.com>
Signed-off-by: Srinidhi Kasagar <srinidhi.kasagar@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Merge branch 'sfi' into release