doc: usage: cmd: reset: specify when the -edl option is available

The option is only available when CONFIG_SYSRESET_QCOM_PSCI is enabled,
so let's make that explicit in the boot cmd documentation.

Due to the implementation in drivers/sysreset/sysreset-uclass.c
do_reset() function, all options to the reset command are passed to all
sysreset drivers' sysreset_ops.request_arg callback (including -w) which
is only available when CONFIG_SYSRESET_CMD_RESET_ARGS=y. -w, however,
works also without this option.

Fixes: ef06c5d76f ("cmd: boot: Add '-edl' option to reset command documentation")
Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

doc/usage/cmd/reset.rst

@@ -11,7 +11,9 @@ Synopsis
 
 ::
 
-    reset [-w]
+    reset
+    reset -w
+    reset -edl
 
 Description
 -----------
@@ -22,8 +24,12 @@ DDR and peripherals, on some boards also resets external PMIC.
 -w
     Do WARM reset: reset CPU but keep peripheral/DDR/PMIC active.
 
+All other options require CONFIG_SYSRESET_CMD_RESET_ARGS=y.
+
 -edl
-    Boot to Emergency DownLoad mode on supported Qualcomm platforms.
+    Boot to Emergency DownLoad mode on supported Qualcomm platforms. Unsupported
+    platforms will print an error message but the command will successfully
+    return (having done nothing). Requires CONFIG_SYSRESET_QCOM_PSCI=y.
 
 Return value
 ------------