MAINTAINERS: adjust file entry in FREESCALE QORIQ DPAA FMAN DRIVER

Commit 243996d1 ("dt-bindings: net: Convert fsl-fman to yaml") splits
the previous dt text file into four yaml files. It adjusts a corresponding
file entry in MAINTAINERS from txt to yaml, but this adjustment misses
that the file was split and renamed.

Hence, ./scripts/get_maintainer.pl --self-test=patterns complains about a
broken reference.

Adjust the file entry to match the four yaml files resulting from this
commit above.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>