i3c: dw: Fix IBI intr programming

IBI_SIR_REQ_REJECT register is not present if the IP has
IC_HAS_IBI_DATA = 1 set. So don't rely on doing read-
modify-write op on this register.
Instead maintain a variable to store the sir reject mask
and use it to set IBI_SIR_REQ_REJECT.

Signed-off-by: Aniket <aniketmaurya@google.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>