vga: fix text mode updating

vga: fix text mode updating

With both text (curses) and graphics (vnc/sdl/spice/...) display active
vga text mode emulation fails to update both correctly.  Depending on
whenever vga_update_text() or vga_draw_text() happens to be called first
only the text display or only the graphics display will see display
resolution changes and full redraws.

Fix it by calling both text/gfx resize functions in both code paths and
keep track of full screen redraws needed in VGACommonState fields.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>