[U-Boot] [PATCH] tools: Add a README note about fw_printenv lock file

[Joe Hershberger]

Add a mention of the lock file to the README for the fw_printenv tool.

Signed-off-by: Joe Hershberger <joe.hershberger at ni.com>
Reported-by: Luka Perkov <uboot at lukaperkov.net>
---
This patch is independent of the series, but should be applied afterward

 tools/env/README | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/env/README b/tools/env/README
index 3f0d77e..df020e4 100644
--- a/tools/env/README
+++ b/tools/env/README
@@ -55,3 +55,7 @@ partition where the environment resides.
 DEVICEx_ENVSECTORS defines the number of sectors that may be used for
 this environment instance. On NAND this is used to limit the range
 within which bad blocks are skipped, on NOR it is not used.
+
+To prevent losing changes to the environment and to prevent confusing the MTD
+drivers, a lock file at /var/lock/fw_printenv.lock is used to serialize access
+to the environment.
-- 
1.7.11.5