splash: Prevent splash_load_fs from writing to 0x0

Passing NULL to fs_read() for actread value results in hanging U-Boot
at least on our ARM plattform (TI AM335x). Since fs_read() and
following functions do not catch nullpointers, writing to 0x0 occurs.

Passing a local dummy var instead of NULL solves this issue.

Signed-off-by: Jonathan Golder <jonathan.golder@kurz-elektronik.de>
Cc: Anatolij Gustschin <agust@denx.de>
diff --git a/common/splash_source.c b/common/splash_source.c
index a5eeb3f..d1647c8 100644
--- a/common/splash_source.c
+++ b/common/splash_source.c
@@ -216,6 +216,7 @@
 {
 	int res = 0;
 	loff_t bmp_size;
+	loff_t actread;
 	char *splash_file;
 
 	splash_file = getenv("splashfile");
@@ -251,7 +252,7 @@
 	}
 
 	splash_select_fs_dev(location);
-	res = fs_read(splash_file, bmp_load_addr, 0, 0, NULL);
+	res = fs_read(splash_file, bmp_load_addr, 0, 0, &actread);
 
 out:
 	if (location->ubivol != NULL)