Add abstract factory to create button iface objects

A abstract factory class is implemented  to return
the instance of button interface class based on the
button iface formfactor name provided as
parameter to the abstract factory createInstance
 method.

Signed-off-by: Naveen Moses <naveen.mosess@hcl.com>
Change-Id: Ia791a2b6f52d09dd87da0e50a709fc72ac9d1bd7
diff --git a/inc/gpio.hpp b/inc/gpio.hpp
index ba4b8ad..ebaf3cf 100644
--- a/inc/gpio.hpp
+++ b/inc/gpio.hpp
@@ -42,14 +42,14 @@
  * @return int returns 0 on successful config of all gpios
  */
 
-int configGroupGpio(sdbusplus::bus::bus& bus, buttonConfig& buttonCfg);
+int configGroupGpio(buttonConfig& buttonCfg);
 
 /**
  * @brief  configures and initializes the single gpio
  * @return int returns 0 on successful config of all gpios
  */
 
-int configGpio(sdbusplus::bus::bus& bus, gpioInfo& gpioConfig);
+int configGpio(gpioInfo& gpioConfig);
 
 uint32_t getGpioNum(const std::string& gpioPin);
 void closeGpio(int fd);