ANDROID: arm64: mark kpti_install_ng_mappings as __nocfi

4.9.93 panics on boot when CFI_CLANG and UNMAP_KERNEL_AT_EL0 are both
enabled.  From Sami Tolvanen:

"kpti_install_ng_mappings makes an indirect call to a physical address,
which trips CFI. Adding the __nocfi attribute to this function should
fix the problem."

Bug: 77811249
Change-Id: I87d1ceb29f1ba2caee8954547596f4236bdfc31f
Reported-by: Jean-Baptiste Theou <jb@essential.com>
Signed-off-by: Greg Hackmann <ghackmann@google.com>