staging: fbtft: fix potential memory leak in fbtft_framebuffer_alloc()

staging: fbtft: fix potential memory leak in fbtft_framebuffer_alloc()

In the error paths after fb_info structure is successfully allocated,
the memory allocated in fb_deferred_io_init() for info->pagerefs is not
freed. Fix that by adding the cleanup function on the error path.

Fixes: c296d5f9957c ("staging: fbtft: core support")
Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/20250626172412.18355-1-abdun.nihaal@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>