lib: sscanf: add sscanf implementation

Port sscanf implementation from mini-os and introduce new
Kconfig option to enable it: CONFIG_SSCANF. Disable by default.

Signed-off-by: Andrii Anisov <andrii_anisov@epam.com>
Signed-off-by: Anastasiia Lukianenko <anastasiia_lukianenko@epam.com>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
diff --git a/lib/Makefile b/lib/Makefile
index 1dc06c5..0cd7bea 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -123,6 +123,7 @@
 # Main U-Boot always uses the full printf support
 obj-y += vsprintf.o strto.o
 obj-$(CONFIG_OID_REGISTRY) += oid_registry.o
+obj-$(CONFIG_SSCANF) += sscanf.o
 endif
 
 obj-y += date.o