[SKIP CI] Tools: Test: Fix upper band limit in THD+N SRC test

[singalsu]

This patch fixes the upper frequency for distortion plus noise measurement. The min(fs1, fs2) leaves part of upper band unmeasured and gives a too good looking THD+N performance figure when output rate is higher than input rate. The proper way is to measure the (near) full output rate bandwidth.

Signed-off-by: Seppo Ingalsuo [email protected]