elf: Add ARC Magic and Relocations

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Workaround a R_ARC_NONE relo generated in dyn-linked executables

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
savedefconfig need not overwrite .config

It now generated a file name defconfig in current directory