ANDROID: x86: kprobes: fix references to optprobe_template_func

optprobe_template_func is not marked as a global symbol, which
conflicts with the C declaration and confuses LLVM when CFI is
enabled. However, marking the symbol global results in a CFI jump
table entry being generated for it, which makes objtool unhappy as the
jump table contains a jump to .rodata.

This change solves both issues by removing the C reference to
optprobe_template_func and generates the STACK_FRAME_NON_STANDARD
entry in inline assembly instead.

Bug: 145210207
Change-Id: Ib19b86cf437277036fa218d6e8d7292f10bef940
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>