uboot-phytec

tools: env: Use getline rather than fgets when reading config/script

When reading the config file, or a script file, use getline rather than
fgets so line lengths aren't limited by the size of a compiled in buffer
(128 characters for config, 1024 for scripts).

Rename 'dump' to 'line' so it's clear we're working with a line of text.

Signed-off-by: Alex Kiernan <alex.kiernan@gmail.com>