The device info table has a different layout when core 2 is in FUS mode.
In particular it's larger than the 32 bytes used when in WS mode and if the
correct amount of space is not allocated then the end of the table may be
overwritten with other data (eg with FUS version 0.5.3). So update the
structure to fix this.
Also update rfcore.py to disable IRQs (which are enabled by rfcore.c), to
not depend on uctypes, and to not require the asm_thumb emitter.
Signed-off-by: Damien George <damien@micropython.org>