PCI: tegra194: Remove unnecessary MSI enable reg save and restore

The integrated MSI Receiver enable register is always initialized in
dw_pcie_setup_rc() which is also called in resume code path, so we
don't need to save/restore the enable register during suspend/resume.

Link: https://lore.kernel.org/r/20211226074910.2722-1-jszhang@kernel.org


Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Vidya Sagar <vidyas@nvidia.com>