UPSTREAM: arm64: assembler: introduce ldr_this_cpu

UPSTREAM: arm64: assembler: introduce ldr_this_cpu

Shortly we will want to load a percpu variable in the return from
userspace path. We can save an instruction by folding the addition of
the percpu offset into the load instruction, and this patch adds a new
helper to do so.

At the same time, we clean up this_cpu_ptr for consistency. As with
{adr,ldr,str}_l, we change the template to take the destination register
first, and name this dst. Secondly, we rename the macro to adr_this_cpu,
following the scheme of adr_l, and matching the newly added
ldr_this_cpu.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Bug: 38331309
Change-Id: Iaaf4ea9674ab89289badee216b5305204172895e
(cherry picked from commit 1b7e2296a822dfd2349960addc42a139360ce769)
Signed-off-by: Zubin Mithra <zsm@google.com>