Convert CONFIG_CHIP_SELECTS_PER_CTRL to Kconfig

This converts the following to Kconfig:
   CONFIG_CHIP_SELECTS_PER_CTRL

Cc: Alison Wang <alison.wang@nxp.com>
Cc: Pramod Kumar <pramod.kumar_1@nxp.com>
Cc: Priyanka Jain <priyanka.jain@nxp.com>
Cc: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Cc: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/kmcent2_defconfig b/configs/kmcent2_defconfig
index 32c9f49..40f471e 100644
--- a/configs/kmcent2_defconfig
+++ b/configs/kmcent2_defconfig
@@ -48,6 +48,7 @@
 CONFIG_BOOTCOUNT_LIMIT=y
 CONFIG_FSL_CAAM=y
 CONFIG_DDR_CLK_FREQ=66666666
+CONFIG_CHIP_SELECTS_PER_CTRL=2
 CONFIG_SYS_FSL_DDR3=y
 CONFIG_DM_I2C=y
 CONFIG_SYS_I2C_FSL=y