soc: arc: optmize and bug fix the compile options

* when -mcpu is given, e.g. -mcpu=em4_dmips,-mnorm,-mdiv_em
etc. are already given, no need to duplicate

* use zephyr_compiler_options to replace zephyr_cc_option
zephyr_cc_option will do compile option check first then add
the checked options into option list. It's too strict that makes
options like -mfpu, -mmpy-option cannot be added.

Signed-off-by: Wayne Ren <wei.ren@synopsys.com>