mcux: Update the README

Update the README to include patch to the CACHE64 driver

Signed-off-by: Mahesh Mahadevan <mahesh.mahadevan@nxp.com>

Author: mmahadevan108

mcux/README

@@ -99,3 +99,4 @@ Patch List:
   - add kUSB_DeviceNotifySOF to usb_device_mcux_drv_port.h SDK USB stack already supports it in SDK 2.16.0
   - mcux-sdk/drivers/adc12/fsl_adc12.c: add guards to avoid compilation warnings when building
       with SDK clock control driver disabled.
+  - Update the driver in mcux-sdk/drivers/cache/cache64/fsl_cache.c to use the non-secure flash address during cache invalidation.