regulator: core: fix constraints output buffer

[ Upstream commit a7068e3932eee8268c4ce4e080a338ee7b8a27bf ]

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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>