arm: tegra: pcie: Fix Coverity issue

Fixed data type mismatch.
As irq was unsigned int following code was skipped always.

Bug 1046331

Change-Id: I5b04c72dfeafb3fb2f2d97cdf4c10fc5ad53dc1b
Signed-off-by: Sri Krishna chowdary <schowdary@nvidia.com>
Reviewed-on: http://git-master/r/131366
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Sachin Nikam <snikam@nvidia.com>