kconfig: NXP IMX: Remove unused HAS_IMX_{RDC,CCM} symbols

The HAS_IMX_{RDC,CCM} symbols were added to ext/hal/nxp/imx/Kconfig in
commit 3afc2b6c ("ext/hal/nxp/imx: Import the nxp imx7 freertos bsp"),
and later copied over to modules/Kconfig.imx in commit 12438e10 ("ext:
hal: Make NXP HALs a Zephyr module").

Never used.

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>