i3c: ast2600: enable IBI support

The ast2600 i3c hardware is capable of IBIs, but we need a workaround
for a hardware issue with the I3C state machine handling IBI payloads
of specific lengths when PEC is not enabled. To avoid this, we need to
unconditionally enable PECs, at the consquence of losing a byte of data
when the device does not send a PEC.

Enable IBIs on the ast2600 platform, including an implementation of the
PEC workaround, which prints a warning when triggered.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/ba923b96d6d129024c975e8a0472c5b2fcb3af32.1680161823.git.jk@codeconstruct.com.au


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>