tests/qtest/ds1338: Reuse from_bcd()

from_bcd() is a public API function which can be unit-tested. Reuse it to avoid
code duplication.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Message-ID: <20251019210303.104718-11-shentey@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

tests/qtest/ds1338-test.c

@@ -18,16 +18,12 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/bcd.h"
 #include "libqtest.h"
 #include "libqos/i2c.h"
 
 #define DS1338_ADDR 0x68
 
-static inline uint8_t bcd2bin(uint8_t x)
-{
-    return ((x) & 0x0f) + ((x) >> 4) * 10;
-}
-
 static void send_and_receive(void *obj, void *data, QGuestAllocator *alloc)
 {
     QI2CDevice *i2cdev = (QI2CDevice *)obj;
@@ -39,9 +35,9 @@ static void send_and_receive(void *obj, void *data, QGuestAllocator *alloc)
     i2c_read_block(i2cdev, 0, resp, sizeof(resp));
 
     /* check retrieved time against local time */
-    g_assert_cmpuint(bcd2bin(resp[4]), == , tm_ptr->tm_mday);
-    g_assert_cmpuint(bcd2bin(resp[5]), == , 1 + tm_ptr->tm_mon);
-    g_assert_cmpuint(2000 + bcd2bin(resp[6]), == , 1900 + tm_ptr->tm_year);
+    g_assert_cmpuint(from_bcd(resp[4]), == , tm_ptr->tm_mday);
+    g_assert_cmpuint(from_bcd(resp[5]), == , 1 + tm_ptr->tm_mon);
+    g_assert_cmpuint(2000 + from_bcd(resp[6]), == , 1900 + tm_ptr->tm_year);
 }
 
 static void ds1338_register_nodes(void)