lib: Improve _parse_integer_fixup_radix base 16 detection

Base autodetection is failing for this case:
if test 257 -gt 3ae; then echo first; else echo second; fi

It is because base for 3ae is recognized by _parse_integer_fixup_radix() as
10. The code detects the first char which is not between 'a'/'A' or 'f'/'F'
to change base from dec to hex.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Shiril Tichkule <shirilt@xlinx.com>

lib/strto.c

@@ -22,9 +22,22 @@ static const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)
 				*base = 16;
 			else
 				*base = 8;
-		} else
+		} else {
+			int i = 0;
+			char var;
+
 			*base = 10;
+
+			do {
+				var = tolower(s[i++]);
+				if (var >= 'a' && var <= 'f') {
+					*base = 16;
+					break;
+				}
+			} while (var);
+		}
 	}
+
 	if (*base == 16 && s[0] == '0' && tolower(s[1]) == 'x')
 		s += 2;
 	return s;