PCI: tegra: Change PRSNT_SENSE IRQ log to debug

PRSNT_MAP bit field is programmed to update the slot present status.
PRSNT_SENSE IRQ is triggered when this bit field is programmed, which is
not an error. Add a new if condition to trap PRSNT_SENSE code and print
it with debug log level.

Signed-off-by: Manikanta Maddireddy <mmaddireddy@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Thierry Reding <treding@nvidia.com>