lib: assume char is unsigned

Now that we use -funsigned-char, there's no need for this kind of ifdef.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

lib/is_signed_type_kunit.c

@@ -21,11 +21,7 @@ static void is_signed_type_test(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, is_signed_type(bool), false);
 	KUNIT_EXPECT_EQ(test, is_signed_type(signed char), true);
 	KUNIT_EXPECT_EQ(test, is_signed_type(unsigned char), false);
-#ifdef __CHAR_UNSIGNED__
 	KUNIT_EXPECT_EQ(test, is_signed_type(char), false);
-#else
-	KUNIT_EXPECT_EQ(test, is_signed_type(char), true);
-#endif
 	KUNIT_EXPECT_EQ(test, is_signed_type(int), true);
 	KUNIT_EXPECT_EQ(test, is_signed_type(unsigned int), false);
 	KUNIT_EXPECT_EQ(test, is_signed_type(long), true);

lib/test_printf.c

@@ -179,18 +179,6 @@ test_number(void)
 	 * behaviour.
 	 */
 	test("00|0|0|0|0", "%.2d|%.1d|%.0d|%.*d|%1.0d", 0, 0, 0, 0, 0, 0);
-#ifndef __CHAR_UNSIGNED__
-	{
-		/*
-		 * Passing a 'char' to a %02x specifier doesn't do
-		 * what was presumably the intention when char is
-		 * signed and the value is negative. One must either &
-		 * with 0xff or cast to u8.
-		 */
-		char val = -16;
-		test("0xfffffff0|0xf0|0xf0", "%#02x|%#02x|%#02x", val, val & 0xff, (u8)val);
-	}
-#endif
 }
 
 static void __init