power: supply: 88pm860x_battery: remove redundant dev_err message

In the pm860x_battery_probe(), when get irq failed, the function
platform_get_irq() logs an dev_err message, so remove redundant
message here.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>