ffspart: Increase MAX_LINE to above PATH_MAX
ffspart: Increase MAX_LINE to above PATH_MAX

Otherwise we saw failures in CI and the ~221 character paths Jankins
likes to have.

Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.ibm.com>
Reviewed-by: Samuel Mendoza-Jonas <f16bed56189e249fe4ca8ed10a1ecae60e8ceac0@mendozajonas.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.ibm.com>

stewart-ibm/skiboot,shenki/skiboot,open-power/skiboot,open-power/skiboot,qemu/skiboot,qemu/skiboot,legoater/skiboot,open-power/skiboot,legoater/skiboot,stewart-ibm/skiboot,open-power/skiboot,qemu/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,shenki/skiboot,shenki/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,stewart-ibm/skiboot,legoater/skiboot,open-power/skiboot