test: Adjust print_ut test to use unsigned char

Since char is unsigned on arm64, this test currently fails. It seems
better to use unsigned anyway, since 0xff is written into the string at
the start. Update the terminator-assert to use a character instead of a
byte.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

Changes in v6:
- Re-introduce

Changes in v2:
- Use '\0' instead of 0

test/print_ut.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/test/common/print.c b/test/common/print.c
index 464e425..e3711b1 100644
--- a/test/common/print.c
+++ b/test/common/print.c
@@ -241,7 +241,7 @@
 
 static int print_hexdump_line(struct unit_test_state *uts)
 {
-	char *linebuf;
+	u8 *linebuf;
 	u8 *buf;
 	int i;
 
@@ -254,10 +254,10 @@
 	linebuf = map_sysmem(0x400, BUF_SIZE);
 	memset(linebuf, '\xff', BUF_SIZE);
 	ut_asserteq(-ENOSPC, hexdump_line(0, buf, 1, 0x10, 0, linebuf, 75));
-	ut_asserteq(-1, linebuf[0]);
+	ut_asserteq(0xff, linebuf[0]);
 	ut_asserteq(0x10, hexdump_line(0, buf, 1, 0x10, 0, linebuf, 76));
-	ut_asserteq(0, linebuf[75]);
-	ut_asserteq(-1, linebuf[76]);
+	ut_asserteq('\0', linebuf[75]);
+	ut_asserteq(0xff, linebuf[76]);
 
 	unmap_sysmem(buf);