net/mlx5: Print health buffer by log level

Add log macro which gets log level as a parameter. Use the severity
read from the health buffer and the new log macro to log the health buffer
with severity as log level.  Prior to this patch, health buffer was
printed in error log level regardless of its severity. Now the user may
filter dmesg (--level) or change kernel log level to focus on different
severity levels of firmware errors.

Signed-off-by: Aya Levin <ayal@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>