wcn36xx: Fix logging macro with unnecessary semicolon

The wcn36xx_err macro should not end in a semicolon as
there are 2 consecutive semicolons in the preprocessed
output.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Eugene Krasnikov <k.eugene.e@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>