include/bcd: move bcd code to commonlib/bsd/include

Move bcd2bin() / bin2bcd() functions to commonlib/bsd/include/

Also, the license is changed from GPL to BSD.
This is because it is needed from "utils" (see CL in the chain).

For reference bin2bcd() & bcd2bin() are very simple functions.
There are already BSD implementations, like these ones (just to
name a few):
https://chromium.googlesource.com/chromiumos/platform/mosys/+/refs/heads/main/include/lib/math.h#67
http://web.mit.edu/freebsd/head/sys/contrib/octeon-sdk/cvmx-cn3010-evb-hs5.c

BUG=b:172210863
TEST=make (everything compiled Ok).

Change-Id: If2eba82da35838799bcbcf38303de6bd53f7eb72
Signed-off-by: Ricardo Quesada <ricardoq@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56904
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/pc80/rtc/mc146818rtc.c

@@ -2,15 +2,15 @@
 
 #include <acpi/acpi.h>
 #include <arch/io.h>
-#include <bcd.h>
-#include <fallback.h>
-#include <version.h>
+#include <commonlib/bsd/bcd.h>
 #include <console/console.h>
+#include <fallback.h>
 #include <pc80/mc146818rtc.h>
 #include <rtc.h>
 #include <security/vboot/vbnv.h>
 #include <security/vboot/vbnv_layout.h>
 #include <types.h>
+#include <version.h>
 
 static void cmos_reset_date(void)
 {