Documentation: fpga: dfl: change FPGA indirect article to an

Change use of 'a fpga' to 'an fpga'

Signed-off-by: Tom Rix <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

Documentation/fpga/dfl.rst

···
 interface to FPGA, e.g. the FPGA Management Engine (FME) and Port (more
 descriptions on FME and Port in later sections).
 
-Accelerated Function Unit (AFU) represents a FPGA programmable region and
+Accelerated Function Unit (AFU) represents an FPGA programmable region and
 always connects to a FIU (e.g. a Port) as its child as illustrated above.
 
 Private Features represent sub features of the FIU and AFU. They could be
···
              | PCI PF Device |            |          | PCI VF Device |
              +---------------+            |          +---------------+
 
-FPGA PCIe device driver is always loaded first once a FPGA PCIe PF or VF device
+FPGA PCIe device driver is always loaded first once an FPGA PCIe PF or VF device
 is detected. It:
 
 * Finishes enumeration on both FPGA PCIe PF and VF device using common