firmware: psci: Fix return value from psci_system_suspend()

Currently we return the value from invoke_psci_fn() directly as return
value from psci_system_suspend(). It is wrong to send the PSCI interface
return value directly. psci_to_linux_errno() provide the mapping from
PSCI return value to the one that can be returned to the callers within
the kernel.

Use psci_to_linux_errno() to convert and return the correct value from
psci_system_suspend().

Fixes: faf7ec4a ("drivers: firmware: psci: add system suspend support")
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20240515095528.1949992-1-sudeep.holla@arm.comSigned-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/firmware/psci/psci.c

@@ -497,10 +497,12 @@ int psci_cpu_suspend_enter(u32 state)
 
 static int psci_system_suspend(unsigned long unused)
 {
+	int err;
 	phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
 
-	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
+	err = invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
 			      pa_cpu_resume, 0, 0);
+	return psci_to_linux_errno(err);
 }
 
 static int psci_system_suspend_enter(suspend_state_t state)