x86: Deactivate kernel options with extra overhead

x86: Deactivate kernel options with extra overhead

Deactivate CONFIG_CONTEXT_TRACKING_USER_FORCE: Force user context
tracking: This is a testing feature which should not be activate in
production environments according to the Kconfig help. It adds an extra
overhead.

Deactivate CONFIG_RCU_NOCB_CPU_DEFAULT_ALL: Offload RCU callback
processing from all CPUs by default: This option should only be used in
aggressive HPC or real-time workloads which we do not have in OpenWrt.
For normal workloads it increases the number of context switches.

In the default Arch Linux kernel both options are not activated.

Fixes: 31111680f6fc ("x86: switch config to a tickless kernel")
Link: https://github.com/openwrt/openwrt/pull/17057
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>