PCI: dwc: Remove unnecessary header include (signal.h)

Remove unnecessary header include (signal.h) since it doesn't provide
any needed symbols.
Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: Jingoo Han <jingoohan1@gmail.com>

drivers/pci/controller/dwc/pcie-designware-plat.c

@@ -16,7 +16,6 @@
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/resource.h>
-#include <linux/signal.h>
 #include <linux/types.h>
 #include <linux/regmap.h>