hw/display/vga: Do not reset 'big_endian_fb' in vga_common_reset()

hw/display/vga: Do not reset 'big_endian_fb' in vga_common_reset()

The 'pci-vga' device allow setting a 'big-endian-framebuffer'
property since commit 3c2784fc864 ("vga: Expose framebuffer
byteorder as a QOM property"). Similarly, the 'virtio-vga'
device since commit 8be61ce2ce3 ("virtio-vga: implement
big-endian-framebuffer property").

Both call vga_common_reset() in their reset handler, respectively
pci_secondary_vga_reset() and virtio_vga_base_reset_hold(), which
reset 'big_endian_fb', overwritting the property. This is not
correct: the hardware is expected to keep its configured
endianness during resets.

Move 'big_endian_fb' assignment from vga_common_reset() to
vga_common_init() which is called once when the common VGA state
is initialized.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Message-Id: <20241129101721.17836-2-philmd@linaro.org>