qca_7k_common: Drop unnecessary function description

qcafrm_fsm_decode has the almost the same function description in
qca_7k_common.c. So drop the comment here.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>