fbdev: goldfishfb: fail pan display on base-update timeout

fbdev: goldfishfb: fail pan display on base-update timeout

goldfish_fb_pan_display() waits for the device to acknowledge the new
framebuffer base, but it only logs a timeout and still reports success.
The probe path also ignores the initial pan-display result before
registering the framebuffer.

Return -ETIMEDOUT when the base-update acknowledgment does not arrive,
and propagate that error from the initial probe-time base update before
the framebuffer is published.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Signed-off-by: Helge Deller <deller@gmx.de>