regulator: core: fix constraints output buffer

commit a7068e3932eee8268c4ce4e080a338ee7b8a27bf upstream.

The buffer for condtraints debug isn't big enough to hold the output
in all cases. So fix this issue by increasing the buffer.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>