fw_env.config: Correct "fw_saveenv" to "fw_setenv".

Fix a comment in the fw_env.config file, no functional change.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
diff --git a/tools/env/fw_env.config b/tools/env/fw_env.config
index 8e21d5a..9d3b1a4 100644
--- a/tools/env/fw_env.config
+++ b/tools/env/fw_env.config
@@ -1,4 +1,4 @@
-# Configuration file for fw_(printenv/saveenv) utility.
+# Configuration file for fw_(printenv/setenv) utility.
 # Up to two entries are valid, in this case the redundant
 # environment sector is assumed present.
 # Notice, that the "Number of sectors" is ignored on NOR and SPI-dataflash.