cmd: increase default for SYS_MAXARGS

The value of CONFIG SYS_MAXARGS limits the usability of the 'for' command.
The current default of 16 is too low for some use case. Cf.
https://bugs.launchpad.net/snap-core18/+bug/1910094

Increase the default to 64.

Reported-by: Dave Jones <dave.jones@canonical.com>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 58ab357..06aae30 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -94,7 +94,7 @@
 
 config SYS_MAXARGS
 	int "Maximum number arguments accepted by commands"
-	default 16
+	default 64
 
 config SYS_XTRACE
 	bool "Command execution tracer"