OMAPDSS: fix compilation warnings

When compiling on x86 we get following warnings:

warning: field width specifier ‘*’ expects argument of type ‘int’, but
argument 5 has type ‘size_t’ [-Wformat]

Fix these by casting the size_t to int.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index c32ec4a..2c871bc 100644
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -3352,7 +3352,7 @@
 
 #define DISPC_REG(i, name) name(i)
 #define DUMPREG(i, r) seq_printf(s, "%s(%s)%*s %08x\n", #r, p_names[i], \
-	48 - strlen(#r) - strlen(p_names[i]), " ", \
+	(int)(48 - strlen(#r) - strlen(p_names[i])), " ", \
 	dispc_read_reg(DISPC_REG(i, r)))
 
 	p_names = mgr_names;
@@ -3429,7 +3429,7 @@
 #define DISPC_REG(plane, name, i) name(plane, i)
 #define DUMPREG(plane, name, i) \
 	seq_printf(s, "%s_%d(%s)%*s %08x\n", #name, i, p_names[plane], \
-	46 - strlen(#name) - strlen(p_names[plane]), " ", \
+	(int)(46 - strlen(#name) - strlen(p_names[plane])), " ", \
 	dispc_read_reg(DISPC_REG(plane, name, i)))
 
 	/* Video pipeline coefficient registers */