You can use cash from the RMD to make a personal IRA contribution, but it is not a rollover. The IRA contribution is a new contribution. Of course you must be eligible to make the IRA contribution.
Several side notes:
If you choose to move the inherited IRA, it must be moved by nonreportable trustee-to-trustee transfer to another inherited IRA (with your mother as deceased owner, for your benefit). It cannot be moved by distribution and rollover.
If your mother died in 2016, just make sure that it is completed by the end of 2016 so that the RMD is not late. However, if your mother died before 2016 you must amend your tax return that you filed for the year of your mother's death by adding Form 5329 to request a waiver of the excess accumulation penalty, based on now having made the late RMD distribution.
