Convert CONFIG_SYS_FSL_NUM_CC_PLLS to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_FSL_NUM_CC_PLLS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/kontron_sl28_defconfig b/configs/kontron_sl28_defconfig
index aaca896..b0b5fb1 100644
--- a/configs/kontron_sl28_defconfig
+++ b/configs/kontron_sl28_defconfig
@@ -24,6 +24,7 @@
 CONFIG_ARMV8_PSCI_RELOCATE=y
 CONFIG_SYS_LOAD_ADDR=0x82000000
 CONFIG_AHCI=y
+CONFIG_SYS_FSL_NUM_CC_PLLS=3
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_HAS_CUSTOM_SYS_INIT_SP_ADDR=y
 CONFIG_CUSTOM_SYS_INIT_SP_ADDR=0x1800eff0