cnss2: Add regulator entry for sleep clock

For some platforms there will be a fixed regulator (GPIO) to supply
sleep clock for WLAN device. Add that entry for power on regulator
list.

Change-Id: I93a44b2466603abc98de17bdbf09c9ddb44ec8ec

cnss2/power.c

@@ -37,6 +37,7 @@ static struct cnss_vreg_cfg cnss_vreg_list[] = {
 	{"vdd-wlan-dig", 950000, 952000, 0, 0, 0},
 	{"vdd-wlan-rfa1", 1900000, 1900000, 0, 0, 0},
 	{"vdd-wlan-rfa2", 1350000, 1350000, 0, 0, 0},
+	{"alt-sleep-clk", 0, 0, 0, 0, 0},
 	{"vdd-wlan-en", 0, 0, 0, 10, 0},
 };