video: fbdev: radeon: Fix memleak in radeonfb_pci_register

When radeon_kick_out_firmware_fb() fails, info should be
freed just like the subsequent error paths.

Fixes: 069ee21a ("fbdev: Fix loading of module radeonfb on PowerMac")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Reviewed-by: Mathieu Malaterre <malat@debian.org>
Cc: Kangjie Lu <kjlu@umn.edu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200825062900.11210-1-dinghao.liu@zju.edu.cn