pcitest.sh: Script now skips MSIs/MSIXs which are not configured

commit 951ef25d7bb361a31fe644238da5c407ae5cd114 from
https://source.codeaurora.org/external/autobsps32/linux



Initially the script tries to send 32 MSIs and 2048 MSIXs, no matter
how many interrupts are enabled on the EP side.
Since the interrupts are generated in order, the script now stops sending
then after the first unsuccessful one.

Issue: ALB-4548

Signed-off-by: Ionut Vicovan <Ionut.Vicovan@nxp.com>
Signed-off-by: Zhantao Tang <zhantao.tang@windriver.com>