MLK-20956 rtc: imx-rpmsg: do NOT overwrite rtc driver data

MLK-20956 rtc: imx-rpmsg: do NOT overwrite rtc driver data

Some test cases need to use RTC driver data, so do NOT
overwrite it using rpmsg data structure.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Bai Ping <ping.bai@nxp.com>
(cherry picked from commit da74fb3d328f037ecb1832a53f45cebdbda8f86f)
Signed-off-by: Arulpandiyan Vadivel <arulpandiyan_vadivel@mentor.com>
Signed-off-by: Shrikant Bobade <Shrikant_Bobade@mentor.com>
(cherry picked from commit 776e5fa2eef90e50cbd90c904c7f880323e8bc33)