wait_chip_ready() and wait_firmware_ready() are never called in atomic
context.  They call mdelay() to busy wait which is not necessary.  mdelay()
can be replaced with msleep().

This is found by a static analysis tool named DCNS written by myself.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>