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

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

After commit 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref
struct"), fb_deferred_io_init() allocates memory for info->pagerefs as
well as return an error code on failure. However the error code is
ignored here and the memory allocated could leak because of not calling
fb_deferred_io_cleanup() on the error path.

Fix them by adding the cleanup function on the error path, and handling
the error code returned by fb_deferred_io_init().

Fixes: 56c134f7f1b5 ("fbdev: Track deferred-I/O pages in pageref struct")
Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/fd2be49cfef72799f17a96d01a4c6b92770cda7d.1751207100.git.abdun.nihaal@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>