video: fbdev: pvr2fb: initialize variables

clang static analysis reports this repesentative error

pvr2fb.c:1049:2: warning: 1st function call argument
is an uninitialized value [core.CallAndMessage]
if (*cable_arg)
^~~~~~~~~~~~~~~

Problem is that cable_arg depends on the input loop to
set the cable_arg[0]. If it does not, then some random
value from the stack is used.

A similar problem exists for output_arg.

So initialize cable_arg and output_arg.

Signed-off-by: Tom Rix <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Sam Ravnborg <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/video/fbdev/pvr2fb.c

···
 	if (!options || !*options)
 		return 0;
 
+	cable_arg[0] = output_arg[0] = 0;
+
 	while ((this_opt = strsep(&options, ","))) {
 		if (!*this_opt)
 			continue;