PowerCap: Add to drivers Kconfig and Makefile

Added changes to Makefile and Kconfig to include in driver build.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/Makefile b/drivers/Makefile
index ab93de8..34c1d55 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -152,3 +152,4 @@
 obj-$(CONFIG_IPACK_BUS)		+= ipack/
 obj-$(CONFIG_NTB)		+= ntb/
 obj-$(CONFIG_FMC)		+= fmc/
+obj-$(CONFIG_POWERCAP)		+= powercap/