retpoline: move setting of sysctl_ibrs_enabled and sysctl_ibpb_enabled to where SPEC_...

retpoline: move setting of sysctl_ibrs_enabled and sysctl_ibpb_enabled to where SPEC_CTRL_IBRS_INUSE and SPEC_CTRL_IBPB_INUSE are set

Move the setting of sysctl_ibrs_enabled and sysctl_ibpb_enabled to the
functions that set SPEC_CTRL_IBRS_INUSE and SPEC_CTRL_IBPB_INUSE.

Orabug: 27625404
Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Conflicts:
	arch/x86/include/asm/spec_ctrl.h