thermal/drivers/thermal_mmio: Remove redundant dev_err call in thermal_mmio_probe()

There is a error message within devm_ioremap_resource already, so
remove the dev_err call to avoid redundant error message.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ruiqi Gong <gongruiqi1@huawei.com>
Acked-by: Talel Shenhar <talel@amazon.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210408100144.7494-1-gongruiqi1@huawei.com