ata: ahci_ceva: Fix id array access in ceva_ahci_read_id()

ATA IDENTIFY command returns an array of le16 words. Accessing it as a
u16 array triggers the following sparse warning:

drivers/ata/ahci_ceva.c:107:33: warning: invalid assignment: &=
drivers/ata/ahci_ceva.c:107:33:    left side has type unsigned short
drivers/ata/ahci_ceva.c:107:33:    right side has type restricted __le16

Use a local variable to explicitly cast the id array to __le16 to avoid
this warning.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>