arm64: Fix build with CC=clang, CONFIG_FTRACE=y and CONFIG_STACK_TRACER=y

arm64: Fix build with CC=clang, CONFIG_FTRACE=y and CONFIG_STACK_TRACER=y

commit 45bd8951806e ("arm64: Improve HAVE_DYNAMIC_FTRACE_WITH_REGS
selection for clang") fixed the build with the above combination by
splitting HAVE_DYNAMIC_FTRACE_WITH_REGS into separate checks for
Clang and GCC.

commit 26299b3f6ba2 ("ftrace: arm64: move from REGS to ARGS") added the
GCC only check "-fpatchable-function-entry=2" back in unconditionally
which breaks the build.

Remove the unconditional check, because the conditional ones were also
updated to _ARGS in the above commit, so they work correctly on their
own.

Fixes: 26299b3f6ba2 ("ftrace: arm64: move from REGS to ARGS")
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20230109122744.1904852-1-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>