Drivers: Explicitly list sr_samplerates fields.

This makes it a bit easier to understand which value means what, just
from looking at the driver code.

hardware/asix-sigma/asix-sigma.c

@@ -70,10 +70,10 @@ static const char *probe_names[NUM_PROBES + 1] = {
 };
 
 static const struct sr_samplerates samplerates = {
-	0,
-	0,
-	0,
-	supported_samplerates,
+	.low  = 0,
+	.high = 0,
+	.step = 0,
+	.list = supported_samplerates,
 };
 
 static const int hwcaps[] = {

hardware/demo/demo.c

@@ -94,10 +94,10 @@ static const int hwcaps[] = {
 };
 
 static const struct sr_samplerates samplerates = {
-	SR_HZ(1),
-	SR_GHZ(1),
-	SR_HZ(1),
-	NULL,
+	.low  = SR_HZ(1),
+	.high = SR_GHZ(1),
+	.step = SR_HZ(1),
+	.list = NULL,
 };
 
 static const char *pattern_strings[] = {

hardware/fx2lafw/fx2lafw.c

@@ -118,10 +118,10 @@ static const uint64_t supported_samplerates[] = {
 };
 
 static const struct sr_samplerates samplerates = {
-	0,
-	0,
-	0,
-	supported_samplerates,
+	.low  = 0,
+	.high = 0,
+	.step = 0,
+	.list = supported_samplerates,
 };
 
 SR_PRIV struct sr_dev_driver fx2lafw_driver_info;

hardware/link-mso19/api.c

@@ -41,12 +41,11 @@ SR_PRIV const char *mso19_probe_names[NUM_PROBES + 1] = {
 	"0", "1", "2", "3", "4", "5", "6", "7", NULL
 };
 
-/*supported samplerates */
 static const struct sr_samplerates samplerates = {
-	SR_HZ(100),
-	SR_MHZ(200),
-	SR_HZ(100),
-	NULL,
+	.low  = SR_HZ(100),
+	.high = SR_MHZ(200),
+	.step = SR_HZ(100),
+	.list = NULL,
 };
 
 SR_PRIV struct sr_dev_driver link_mso19_driver_info;

hardware/openbench-logic-sniffer/api.c

@@ -44,12 +44,12 @@ SR_PRIV const char *ols_probe_names[NUM_PROBES + 1] = {
 	NULL,
 };
 
-/* default supported samplerates, can be overridden by device metadata */
+/* Default supported samplerates, can be overridden by device metadata. */
 static const struct sr_samplerates samplerates = {
-	SR_HZ(10),
-	SR_MHZ(200),
-	SR_HZ(1),
-	NULL,
+	.low  = SR_HZ(10),
+	.high = SR_MHZ(200),
+	.step = SR_HZ(1),
+	.list = NULL,
 };
 
 SR_PRIV struct sr_dev_driver ols_driver_info;

hardware/zeroplus-logic-cube/zeroplus.c

@@ -126,10 +126,10 @@ static const uint64_t supported_samplerates[] = {
 };
 
 static const struct sr_samplerates samplerates = {
-	0,
-	0,
-	0,
-	supported_samplerates,
+	.low  = 0,
+	.high = 0,
+	.step = 0,
+	.list = supported_samplerates,
 };
 
 /* Private, per-device-instance driver context. */