memory: ti-gpmc: Alloc per driver private struct

Driver uses dev_get_priv() but never allocates it in its
declaration leading to various crashes. Fix this by explicitly
allocating the storage.

Fixes: 9b0b5648d6 ("memory: Add TI GPMC driver")
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>

drivers/memory/ti-gpmc.c

@@ -1242,4 +1242,5 @@ U_BOOT_DRIVER(ti_gpmc) = {
 	.of_match = gpmc_dt_ids,
 	.probe  = gpmc_probe,
 	.flags  = DM_FLAG_ALLOC_PRIV_DMA,
+	.priv_auto = sizeof(struct ti_gpmc),
 };