Documentation: nommu-map: Fix duplicate word typo

           appropriate mapping protection capabilities. Ramfs, romfs, cramfs

           and mtd might all permit this.

	 - If the backing device device can't or won't permit direct sharing,

	 - If the backing device can't or won't permit direct sharing,

           but does have the NOMMU_MAP_COPY capability, then a copy of the

           appropriate bit of the file will be read into a contiguous bit of

           memory and any extraneous space beyond the EOF will be cleared