This also moves bb_get_chunk_with_continuation into its sole user,
parse_config.c.
This allows to optimize both functions separately,
they need to be optimized for speed.
(this need was highlighted by slow modprobe caused in part by slow
bb_get_chunk_with_continuation in config parser).
function old new delta
bb_get_chunk_from_file 7 130 +123
config_read 457 558 +101
bb_get_chunk_with_continuation 194 - -194
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 2/0 up/down: 224/-194) Total: 30 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>