media: imx274: select REGMAP_I2C

The imx274 driver uses regmap and the build will fail without it.

Fixes:

  drivers/media/i2c/imx274.c:142:21: error: variable ‘imx274_regmap_config’ has initializer but incomplete type
   static const struct regmap_config imx274_regmap_config = {
                       ^~~~~~~~~~~~~
  drivers/media/i2c/imx274.c:1869:19: error: implicit declaration of function ‘devm_regmap_init_i2c’ [-Werror=implicit-function-declaration]
    imx274->regmap = devm_regmap_init_i2c(client, &imx274_regmap_config);
                     ^~~~~~~~~~~~~~~~~~~~

and others.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>