cmd: mdc/mwc: normalize disjoint MX_CYCLIC usage

Both CMD_MX_CYCLIC and MX_CYCLIC are in use and defined in Kconfig,
but only the non-CMD version currently does anything. This changes all
usages to prefer the CMD_MX_CYCLIC option (since it's only affecting
addition of the commands), and switches defconfigs using the non-CMD
version to use the CMD version.

Signed-off-by: Joel Johnson <mrjoel@lixil.net>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/k2hk_evm_defconfig b/configs/k2hk_evm_defconfig
index f948e24..4cd8647 100644
--- a/configs/k2hk_evm_defconfig
+++ b/configs/k2hk_evm_defconfig
@@ -25,7 +25,7 @@
 CONFIG_SPL_POWER_SUPPORT=y
 CONFIG_SPL_SPI_LOAD=y
 CONFIG_SYS_SPI_U_BOOT_OFFS=0x10000
-CONFIG_MX_CYCLIC=y
+CONFIG_CMD_MX_CYCLIC=y
 # CONFIG_CMD_FLASH is not set
 # CONFIG_CMD_GPIO is not set
 # CONFIG_CMD_GPT is not set