docs/runfvp: add FVP_BINDIR configuration information

Related commit information is given below for reference.

[1/1] arm/classes: add support to configure fvp-bindir
      commit: 42390742b10a62658d7cdd941d7f8f26c185c38a

Signed-off-by: Mohammed Javith Akthar M <mohammedjavitham@ami.com>
Signed-off-by: Jon Mason <jon.mason@arm.com>

documentation/runfvp.md

@@ -59,6 +59,16 @@ There are recipes for common FVPs in meta-arm already, and writing new recipes i
 
 If `FVP_PROVIDER` is not set then it is assumed that `FVP_EXE` is installed on the host already.
 
+### `FVP_BINDIR`
+
+Optional parameter to configure the path of the FVP binary. For example, `fvp-base` uses path from the build host by default. This path can be customized by configuring like below.
+
+```
+FVP_BINDIR ?= "utilities/fvp/usr/bin"
+```
+
+Potential use case for this parameter configuration is to execute `runfvp` script without the need for bitbake environment initialization.
+
 ### `FVP_CONFIG`
 
 Parameters passed to the FVP with the `--parameter`/`-C` option.  These are expressed as variable flags so individual parameters can be altered easily. For example: