firmware: arm_scmi: Fix wrong fastchannel initialization

Fastchannels are initialized with an incorrect index(POWERCAP_PAI_GET) in:
commit 2441caa8 ("firmware: arm_scmi: Populate fast channel rate_limit")

Fix this and provide a correct index(POWERCAP_FC_PAI)

Fixes: 2441caa8 ("firmware: arm_scmi: Populate fast channel rate_limit")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202403100744.7Op3PI8L-lkp@intel.com/Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Link: https://lore.kernel.org/r/20240311090413.1710725-1-pierre.gondois@arm.comSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/powercap.c

@@ -736,7 +736,7 @@ static void scmi_powercap_domain_init_fc(const struct scmi_protocol_handle *ph,
 	ph->hops->fastchannel_init(ph, POWERCAP_DESCRIBE_FASTCHANNEL,
 				   POWERCAP_PAI_GET, 4, domain,
 				   &fc[POWERCAP_FC_PAI].get_addr, NULL,
-				   &fc[POWERCAP_PAI_GET].rate_limit);
+				   &fc[POWERCAP_FC_PAI].rate_limit);
 
 	*p_fc = fc;
 }