i2c: imx-lpi2c: select CONFIG_I2C_SLAVE

The addition of target mode causes a build failure when CONFIG_I2C_SLAVE
is turned off:

drivers/i2c/busses/i2c-imx-lpi2c.c:1273:10: error: 'const struct i2c_algorithm' has no member named 'reg_target'
 1273 |         .reg_target     = lpi2c_imx_register_target,
      |          ^~~~~~~~~~
drivers/i2c/busses/i2c-imx-lpi2c.c:1274:10: error: 'const struct i2c_algorithm' has no member named 'unreg_target'
 1274 |         .unreg_target   = lpi2c_imx_unregister_target,
      |          ^~~~~~~~~~~~

Select the Kconfig symbol like we do for other similar drivers.

Fixes: 1ee867e ("i2c: imx-lpi2c: add target mode support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Author: arndb

drivers/i2c/busses/Kconfig

@@ -756,6 +756,7 @@ config I2C_IMX
 config I2C_IMX_LPI2C
 	tristate "IMX Low Power I2C interface"
 	depends on ARCH_MXC || COMPILE_TEST
+	select I2C_SLAVE
 	help
 	  Say Y here if you want to use the Low Power IIC bus controller
 	  on the Freescale i.MX processors.