drivers/fpga/Kconfig: fix build failure

While building m32r allmodconfig the build is failing with the error:

  ERROR: "bad_dma_ops" [drivers/fpga/zynq-fpga.ko] undefined!

Xilinx Zynq FPGA is using DMA but there was no dependency while
building.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Sudip Mukherjee <[email protected]>
Acked-by: Moritz Fischer <[email protected]>
Cc: Alan Tull <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

drivers/fpga/Kconfig

@@ -21,6 +21,7 @@ config FPGA_MGR_SOCFPGA
 
 config FPGA_MGR_ZYNQ_FPGA
 	tristate "Xilinx Zynq FPGA"
+	depends on HAS_DMA
 	help
 	  FPGA manager driver support for Xilinx Zynq FPGAs.