ANDROID: arm64: add __pa_function

We use non-canonical CFI jump tables with CONFIG_CFI_CLANG, which
means the compiler replaces function address references with the
address of the function's CFI jump table entry. This results in
__pa_symbol(function) returning the physical address of the jump
table entry, which can lead to address space confusion since the
jump table points to a virtual address.

This change adds a __pa_function macro, which uses inline assembly
to take the actual function address instead.

Bug: 145210207
Change-Id: I14995e522365ad09a5c9bd676e1203b2b642cd5a
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>