doc: we do not need gcc-c++.i686 on fedora
doc: we do not need gcc-c++.i686 on fedora

This package is not needed for building on fedora and currently causes
dependency issue with the fedora package manager, so remove it.

Fixes #6013

Signed-off-by: Anas Nashif <0d9952ec84ac43c159f6b7e7ed99a9080c00dd6e@intel.com>

Vudentz/zephyr,finikorg/zephyr,ldts/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,galak/zephyr,punitvara/zephyr,kraj/zephyr,finikorg/zephyr,mbolivar/zephyr,zephyriot/zephyr,ldts/zephyr,Vudentz/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,GiulianoFranchetto/zephyr,Vudentz/zephyr,kraj/zephyr,kraj/zephyr,ldts/zephyr,explora26/zephyr,zephyriot/zephyr,zephyriot/zephyr,finikorg/zephyr,explora26/zephyr,explora26/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,punitvara/zephyr,nashif/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,punitvara/zephyr,mbolivar/zephyr,kraj/zephyr,ldts/zephyr,explora26/zephyr,galak/zephyr,zephyriot/zephyr,explora26/zephyr,zephyriot/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,mbolivar/zephyr,kraj/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,nashif/zephyr,galak/zephyr