PCI: dwc: Replace lower into upper case characters

Replace of all initial lowercase character in comments and debug messages
to uppercase to maintain coherence.

Fix messages coherence within the DesignWare driver.

Fix code style on dw_pcie_irq_domain_free() function.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
Acked-by: Joao Pinto <jpinto@synopsys.com>