scripts: LDFLAGS CFLAGS and LD values need change

LDFLAGS is set to use gcc as ld, then LD required to be set to gcc
LDFLAGS and CFLAGS are very long and multilines is more readable
script: the target output directory name changes

from out/target/<BOARD>/
to out/target/<CONFIGNAME>/
configs: server configuration file for snowball
kernel: CFLAGS and LDFLAGS change . kernel variable name change

linux kernel uses "ld" as linker and not "gcc" as other package