For some config options (CONFIG_EXTRA_FIRMWARE, for example), the length
of a config file line can exceed the 1024 byte buffer.

Switch from fgets to compat_getline to fix. compat_getline is an
internally implimented getline work-alike for portability purposes.
Signed-off-by: NCody Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>