lib: provide function hextoull()

We often convert hexadecimal strings to hextoull(). Provide a wrapper
function to simple_strtoull() that does not require specifying the radix.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
diff --git a/lib/strto.c b/lib/strto.c
index f83ac67..206d1e9 100644
--- a/lib/strto.c
+++ b/lib/strto.c
@@ -78,6 +78,11 @@
 	return simple_strtoul(cp, endp, 16);
 }
 
+unsigned long long hextoull(const char *cp, char **endp)
+{
+	return simple_strtoull(cp, endp, 16);
+}
+
 ulong dectoul(const char *cp, char **endp)
 {
 	return simple_strtoul(cp, endp, 10);