aon_counter test: fix misspelling in the header include guard

The include guard has a misspelling.

Jira: ZEP-1746

Change-Id: I4d8000ef5c8e037f80acbf2491d0b9466670816a
Signed-off-by: Kuo-Lang Tseng <kuo-lang.tseng@intel.com>
1 file changed