[doc] Document the requirement for OpenOCD 0.11

After a rather extensive release cycle the OpenOCD finally produced an
upstream stable release with RISC-V support. This allows us to switch
back to the normal upstream version of OpenOCD, which will soon also
appear in distribution.

CI is already using OpenOCD 0.11.0 (rc2 before, since today the final
0.11.0 release), giving us the confidence that what we document actually
works.

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/doc/ug/getting_started_fpga.md b/doc/ug/getting_started_fpga.md
index 0d7539f..5c6d1ac 100644
--- a/doc/ug/getting_started_fpga.md
+++ b/doc/ug/getting_started_fpga.md
@@ -195,11 +195,10 @@
 
 ```console
 $ cd $REPO_TOP
-$ /tools/openocd/bin/openocd -s util/openocd -f board/lowrisc-earlgrey-nexysvideo.cfg
+$ openocd -s util/openocd -f board/lowrisc-earlgrey-nexysvideo.cfg
 ```
 
-Note that you must use the [RISC-V fork of OpenOCD](https://github.com/riscv/riscv-openocd).
-See the [install instructions]({{< relref "install_instructions#openocd" >}}) for guidance on building OpenOCD.
+See the [install instructions]({{< relref "install_instructions#openocd" >}}) for guidance on installing OpenOCD.
 
 To actually debug through OpenOCD, it must either be connected through telnet or GDB.