mtd: nand: brcmnand: Change BUG_ON in brcmnand_send_cmd

Change the BUG_ON() condition in brcmnand_send_cmd() which checks for
the interrupt status "controller ready" bit to a WARN_ON.

There is no good reason to kill the system when this condition occur
because we could have systems which listed the NAND controller as
available (e.g: from Device Tree), but the NAND chip could be
malfunctioning and not responding.

Signed-off-by: Florian Fainelli <[e-mail]>
Acked-by: Brian Norris <[e-mail]>
Reviewed-by: Kamal Dasu <[e-mail]>
Signed-off-by: Brian Norris <[e-mail]>

drivers/mtd/nand/brcmnand/brcmnand.c

···
 	ctrl->cmd_pending = cmd;
 
 	intfc = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS);
-	BUG_ON(!(intfc & INTFC_CTLR_READY));
+	WARN_ON(!(intfc & INTFC_CTLR_READY));
 
 	mb(); /* flush previous writes */
 	brcmnand_write_reg(ctrl, BRCMNAND_CMD_START,