qsap: Add API to get device mac address based on interface name.

This adds new API linux_get_ifhwaddr() which can be used to get
mac address of input interface. IOCTL SIOCGIFHWADDR is used to get
the interface address.

CRs-Fixed: 2080924
Change-Id: I1b825fb2c1f35280d2d57928be4f87d23d78decb

softap/sdk/qsap_api.h

@@ -618,6 +618,7 @@ int qsap_prepare_softap(void);
 int qsap_unprepare_softap(void);
 int qsap_is_fst_enabled(void);
 int qsap_control_bridge(int argc, char ** argv);
+int linux_get_ifhwaddr(const char *ifname, char *addr);
 
 #if __cplusplus
 };  // extern "C"