ASoC: Remove bogus check for register validity in debugfs write

Since not all registers need to be cached and the cache is entirely
optional anyway we shouldn't be checking that a register is in the
cached range. If the register is invalid then the actual I/O code
can determine that and report an error.

Similarly, the step size can and should be enforced by the lower level
code if it's important.

Signed-off-by: Mark Brown <[e-mail]>
Acked-by: Liam Girdwood <[e-mail]>

sound/soc/soc-core.c

···
 	while (*start == ' ')
 		start++;
 	reg = simple_strtoul(start, &start, 16);
-	if ((reg >= codec->driver->reg_cache_size) || (reg % step))
-		return -EINVAL;
 	while (*start == ' ')
 		start++;
 	if (strict_strtoul(start, 16, &value))