If you are only interested in GRIB functionality, then you can delete the BUFR-related tables/definitions from the install tree e.g. rm -rf /path/to/install/share/eccodes/definitions/bufr
If Likewise, if you are only interested in BUFR functionality, then you can delete the GRIB-related tables/definitionsfrom the install tree e.g. rm -rf /path/to/install/share/eccodes/definitions/grib[123]
You can also delete some of the executables in the "bin" directory e.g. commands starting with the "bufr_" can be deleted if you are only interested in GRIB