ata: pata_pdc2027x: Replace mdelay with msleep

After checking all possible call chains to pdc_adjust_pll and
pdc_detect_pll_input_clock,
my tool finds that these functions are never called in atomic context,
namely never in an interrupt handler or holding a spinlock.
And their caller functions pdc2027x_init_one and pdc2027x_reinit_one
calls pci_enable_device which can sleep, and no spinlock is held when
calling pdc_adjust_pll and pdc_detect_pll_input_clock,
so it proves that pdc_adjust_pll and pdc_detect_pll_input_clock
can call functions which can sleep.
Thus mdelay can be replaced with msleep to avoid busy wait.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>