ANDROID: arm64: lse: fix LSE atomics with LTO

LLVM's integrated assembler is always used for inline assembly with
CONFIG_LTO_CLANG. Unlike gcc, LLVM considers each inline assembly
block to be independent and therefore, any preambles that enable
features must be included in each block.

This change adds the necessary preamble to ARM64_LSE_ATOMIC_INSN to
allow CONFIG_ARM64_LSE_ATOMICS to be enabled with LTO.

Bug: 117299373
Bug: 133186739
Change-Id: Icc06361dc2a2dba0f5f967d7f540cac2753b3e9c
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>