Clean up compiler warning in port.c.

v2 - reformat commit message

Gcc (and presumably other compilers) emits a warning about the
declaration of 'dscmp' shadowing a global declaration in bmc.h.
This warning is completely benign but makes it more difficult to
recognize warnings that might be consequential.

This patch renames the variable 'dscmp' to 'clk_dscmp'.

Signed-off-by: Michael Galassi <michael@galassi.us>

port.c

diff --git a/port.c b/port.c
index 957c5fe..95460a4 100644
--- a/port.c
+++ b/port.c
@@ -2768,11 +2768,11 @@
 
 struct foreign_clock *port_compute_best(struct port *p)
 {
-	int (*dscmp)(struct dataset *a, struct dataset *b);
+	int (*clk_dscmp)(struct dataset *a, struct dataset *b);
 	struct foreign_clock *fc;
 	struct ptp_message *tmp;
 
-	dscmp = clock_dscmp(p->clock);
+	clk_dscmp = clock_dscmp(p->clock);
 	p->best = NULL;
 
 	if (p->master_only)
@@ -2792,7 +2792,7 @@
 
 		if (!p->best)
 			p->best = fc;
-		else if (dscmp(&fc->dataset, &p->best->dataset) > 0)
+		else if (clk_dscmp(&fc->dataset, &p->best->dataset) > 0)
 			p->best = fc;
 		else
 			fc_clear(fc);