lib: test_scanf: Add tests for sscanf number conversion

Adds test_sscanf to test various number conversion cases, as
number conversion was previously broken.

This also tests the simple_strtoxxx() functions exported from
vsprintf.c.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210514161206.30821-3-rf@opensource.cirrus.com
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2c7f46b..dc437a1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2163,6 +2163,9 @@
 config TEST_PRINTF
 	tristate "Test printf() family of functions at runtime"
 
+config TEST_SCANF
+	tristate "Test scanf() family of functions at runtime"
+
 config TEST_BITMAP
 	tristate "Test bitmap_*() family of functions at runtime"
 	help