Answer
HBr is the stronger acid.
Work Step by Step
Since $HBr$ completely dissociates in aqueous solution and $HBrO$ doesn't , $HBr$ will be the stronger acid.
*$HBr$ is one of the common strong acids.
$K_a (HBrO) = 2.8 \times 10^{-9}$
$K_a(HBr) \approx 10^9$