MAINTAINERS: add backup FPGA maintainer

Add Moritz as a maintainer of the kernel FPGA framework.
Signed-off-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -5419,7 +5419,7 @@ K:	fmc_d.*register
 
 FPGA MANAGER FRAMEWORK
 M:	Alan Tull <atull@kernel.org>
-R:	Moritz Fischer <mdf@kernel.org>
+M:	Moritz Fischer <mdf@kernel.org>
 L:	linux-fpga@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/atull/linux-fpga.git