tools: PCI: Fix compilation warnings

Current compilation produces the following warnings:

tools/pci/pcitest.c: In function 'run_test':
tools/pci/pcitest.c:56:9: warning: unused variable 'time'
[-Wunused-variable]
  double time;
         ^~~~
tools/pci/pcitest.c:55:25: warning: unused variable 'end'
[-Wunused-variable]
  struct timespec start, end;
                         ^~~
tools/pci/pcitest.c:55:18: warning: unused variable 'start'
[-Wunused-variable]
  struct timespec start, end;
                  ^~~~~
tools/pci/pcitest.c:146:1: warning: control reaches end of non-void
function [-Wreturn-type]
 }
 ^

Fix them:
 - remove unused variables
 - change function return from int to void, since it's not used

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
[lorenzo.pieralisi@arm.com: rewrote the commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Kishon Vijay Abraham I <kishon@ti.com>

tools/pci/pcitest.c

@@ -23,7 +23,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/ioctl.h>
-#include <time.h>
 #include <unistd.h>
 
 #include <linux/pcitest.h>
@@ -48,17 +47,15 @@ struct pci_test {
 	unsigned long	size;
 };
 
-static int run_test(struct pci_test *test)
+static void run_test(struct pci_test *test)
 {
 	long ret;
 	int fd;
-	struct timespec start, end;
-	double time;
 
 	fd = open(test->device, O_RDWR);
 	if (fd < 0) {
 		perror("can't open PCI Endpoint Test device");
-		return fd;
+		return;
 	}
 
 	if (test->barnum >= 0 && test->barnum <= 5) {