Registering mortgaged property to mortgagee

Your query is not clear. What do you mean by registering of mortgage property in favor of mortgagee? Whether it is sale according to you ?

If you mean it a sale, I don't think there is any bar in law since the mortgagor and mortgagee  can have such an arrangement if the defaulted mortgage money is to be adjusted out of the sale consideration. Then the mortgage is deemed to be redeemed in toto as sale in favour of the mortgagee wipes off the earlier transaction i.e. the mortgage by supercession. If that was the idea of the mortgaor he could have 'mortgaged the propertry  by conditional sale' to avoid stamp duty and registration being unwarranted expenditure. 

Its a simple mortgage. Since mortgagor can't pay the mortgage money, mortgagor decided to register/sale the property in favor of mortgagee in registration office . The mortgage money is equal to the value of the property.

Sale of the mortgaged property to the mortgagee is not prohibited in law. It can be done in supercession of the mortgage so it would be easy for liquidation of the debt without incurring extra expenditure except stamp duty and registration charges.