Currently, vkms doesn't support any reflection property. Therefore, add
the reflect-x property to vkms through a software implementation of the
operation. This is possible by reverse reading the x axis during the
blending.

Tested with igt@kms_rotation_crc@primary-reflect-x [1] and
igt@kms_rotation_crc@sprite-reflect-x [1].

[1] https://patchwork.freedesktop.org/series/116025/Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230418130525.128733-3-mcanal@igalia.com