spi: img-spfi: Fix pm_runtime_get_sync() error checking

If the device is already in a runtime PM enabled state
pm_runtime_get_sync() will return 1, so a test for negative
value should be used to check for errors.

Fixes: deba2580 ("spi: Add driver for IMG SPFI controller")
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Link: https://lore.kernel.org/r/20220422062641.10486-1-zhengyongjun3@huawei.com


Signed-off-by: Mark Brown <broonie@kernel.org>