doc: Use "changesets" not "csets" in statistics pages

To make things more human readable, say "changesets from" rather than
"csets from" in all our historical pages here. Moving forward this has
been changed in our gitdm with b034e399e31a ("gitdm: fix typo csets").

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/doc/develop/statistics/u-boot-stats-v2010.06.rst b/doc/develop/statistics/u-boot-stats-v2010.06.rst
index 7234874..ddd59ee 100644
--- a/doc/develop/statistics/u-boot-stats-v2010.06.rst
+++ b/doc/develop/statistics/u-boot-stats-v2010.06.rst
@@ -3,7 +3,7 @@
 Release Statistics for U-Boot v2010.06
 ======================================
 
-* Processed 402 csets from 100 developers
+* Processed 402 changesets from 100 developers
 
 * 31 employers found