i2c: designware: fix spelling mistakes

Trivial fixes to spelling mistakes in dev_dbg message

"STAUTS" -> "STATUS"
"SLAVE_ACTTVITY" -> "SLAVE_ACTIVITY"

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>