Cleanup in sysdep KRT code, part 1.

OS-dependent functions renamed to be more consistent,
prepared to merge krt-set and krt-scan headers.

Name changes:

struct krt_if_params -> struct kif_params
struct krt_if_status -> struct kif_status
struct krt_set/scan_params -> struct krt_params
struct krt_set/scan_status -> struct krt_status

krt_if_params_same -> kif_sys_reconfigure
krt_if_copy_params -> kif_sys_copy_config
krt_set/scan_params_same -> krt_sys_reconfigure
krt_set/scan_copy_params -> krt_sys_copy_config

krt_if_scan -> kif_do_scan
krt_set_notify -> krt_do_notify
krt_scan_fire -> krt_do_scan

krt_if_ -> kif_sys_
krt_scan_ -> krt_sys_
krt_set_ -> krt_sys_