regmap: remove stray space

There are two spaces between arguments in regmap_fields_update_bits_base()
so remove one.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20200615072507.11303-1-brgl@bgdev.plSigned-off-by: Mark Brown <broonie@kernel.org>