FreeRTOS v11 support

[eamars]

Hello All
Given the FreeRTOS v11 is released at the end of 2023, the pico-sdk,especially the functions that supports SMP, needed to be updated to support the new flag to properly incorporate with SMP.

For example
https://github.com/raspberrypi/pico-sdk/blob/master/src/rp2_common/pico_async_context/async_context_freertos.c#L15

The code

#if configNUM_CORES > 1 && !defined(configUSE_CORE_AFFINITY)
#error async_context_freertos requires configUSE_CORE_AFFINITY under SMP
#endif

Should be updated to look for the new config configNUMBER_OF_CORES.
There are more files need to be updated.

Reference:
https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/smp/README.md

[peterharperuk]

#1530

We suspect there might be more work to do

[eamars]

Thanks for pointing this out @peterharperuk
I'm testing the compatibility of FreeRTOS v11 with Picosdk right now and haven't found any issues so far.