drm: generic fn converting be24 to cpu and vice versa

Existing functions for converting a 3bytes(be24) of big endian value
into u32 of little endian and vice versa are renamed as

s/drm_hdcp2_seq_num_to_u32/drm_hdcp_be24_to_cpu
s/drm_hdcp2_u32_to_seq_num/drm_hdcp_cpu_to_be24

Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Suggested-by: Daniel Vetter <daniel@ffwll.ch>
cc: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190507162745.25600-4-ramalingam.c@intel.com

drivers/misc/mei/hdcp/mei_hdcp.c

@@ -576,7 +576,7 @@ static int mei_hdcp_verify_mprime(struct device *dev,
 
 	memcpy(verify_mprime_in.m_prime, stream_ready->m_prime,
 	       HDCP_2_2_MPRIME_LEN);
-	drm_hdcp2_u32_to_seq_num(verify_mprime_in.seq_num_m, data->seq_num_m);
+	drm_hdcp_cpu_to_be24(verify_mprime_in.seq_num_m, data->seq_num_m);
 	memcpy(verify_mprime_in.streams, data->streams,
 	       (data->k * sizeof(struct hdcp2_streamid_type)));