lib/hexdump.c: return -EINVAL in case of error in hex2bin()

In some cases caller would like to use error code directly without
shadowing.

-EINVAL feels a rightful code to return in case of error in hex2bin().

Link: http://lkml.kernel.org/r/20170731135510.68023-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/hexdump.c

@@ -9,6 +9,7 @@
 
 #include <linux/types.h>
 #include <linux/ctype.h>
+#include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <asm/unaligned.h>
@@ -42,7 +43,7 @@ EXPORT_SYMBOL(hex_to_bin);
  * @src: ascii hexadecimal string
  * @count: result length
  *
- * Return 0 on success, -1 in case of bad input.
+ * Return 0 on success, -EINVAL in case of bad input.
  */
 int hex2bin(u8 *dst, const char *src, size_t count)
 {
@@ -51,7 +52,7 @@ int hex2bin(u8 *dst, const char *src, size_t count)
 		int lo = hex_to_bin(*src++);
 
 		if ((hi < 0) || (lo < 0))
-			return -1;
+			return -EINVAL;
 
 		*dst++ = (hi << 4) | lo;
 	}