fbdev: Remove FBINFO_DEFAULT from kzalloc()'ed structs

The flag FBINFO_DEFAULT is 0 and has no effect, as struct fbinfo.flags
has been allocated to zero by kzalloc(). So do not set it.

Flags should signal differences from the default values. After cleaning
up all occurrences of FBINFO_DEFAULT, the token will be removed.

v4:
	* clarify commit message (Geert, Dan)
v2:
	* fix commit message (Miguel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Russell King <linux@armlinux.org.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20230715185343.7193-4-tzimmermann@suse.de