[COMMON] media: mfc: DRV4.0: delete mfc_inst

[COMMON] media: mfc: DRV4.0: delete mfc_inst

Ths mfc_inst is similar to mfc_cmd, so it is merged to cmd.
In this process, the following changes were made.

< merge >
- mfc_open_inst => mfc_cmd_open_inst
- mfc_close_inst => mfc_cmd_close_inst
< rename >
- mfc_abort_inst => mfc_cmd_abort_inst
- mfc_init_decode => mfc_cmd_init_decode
- mfc_decode_one_frame => mfc_cmd_dec_one_frame
- mfc_init_encode => mfc_cmd_init_encode
- mfc_encode_one_frame => mfc_cmd_enc_one_frame
< move >
- mfc_h264_set_aso_slice_order =>
	mfc_set_aso_slice_order_h264 in enc_param.c
< add >
- mfc_set_enc_params() in enc_param.c

And unnecessary code in mfc_cmd has been removed.

Change-Id: I638f02ff0100921f2e82c19ed1089538a6add0c1
Signed-off-by: Sunyoung Kang <sy0816.kang@samsung.com>