firmware: arm_scmi: Set clock latency to U32_MAX if it is not supported

As per the spec, the clock_enable_delay is the worst case latency
incurred by the platform to enable the clock. The value of 0 indicates
that the platform doesn't support the same and must be considered as
maximum latency for practical purposes.

Currently the value of 0 is assigned as is and is propogated to the clock
framework which can assume that the clock can support atomic enable operation.

Link: https://lore.kernel.org/r/20220428122913.1654821-1-sudeep.holla@arm.com
Fixes: 18f295b7 ("firmware: arm_scmi: Add support for clock_enable_latency")
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/clock.c

@@ -6,6 +6,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/limits.h>
 #include <linux/sort.h>
 
 #include "protocols.h"
@@ -128,12 +129,13 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
 
 	ret = ph->xops->do_xfer(ph, t);
 	if (!ret) {
+		u32 latency = 0;
 		attributes = le32_to_cpu(attr->attributes);
 		strlcpy(clk->name, attr->name, SCMI_MAX_STR_SIZE);
 		/* Is optional field clock_enable_latency provided ? */
 		if (t->rx.len == sizeof(*attr))
-			clk->enable_latency =
-				le32_to_cpu(attr->clock_enable_latency);
+			latency = le32_to_cpu(attr->clock_enable_latency);
+		clk->enable_latency = latency ? : U32_MAX;
 	}
 
 	ph->xops->xfer_put(ph, t);