firmware: scmi: smt: Interrupt communication enable

firmware: scmi: smt: Interrupt communication enable

i.MX95 System Manager uses interrupt driven communication which requires
the caller to set Bit[0] of channel flags to 1. When transmission
completes and the previous general purpose interrupt has been processed
by the other core, i.MX95 System Manager will set General Purpose
Interrupt Control Register (GCR). U-Boot polls General-purpose Status
(GSR) to check if the operation is finished.

Signed-off-by: Viorel Suman <viorel.suman@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Marek Vasut <marex@denx.de>