UPSTREAM: arm64: tls: Avoid unconditional zeroing of tpidrro_el0 for native tasks

When unmapping the kernel at EL0, we use tpidrro_el0 as a scratch register
during exception entry from native tasks and subsequently zero it in
the kernel_ventry macro. We can therefore avoid zeroing tpidrro_el0
in the context-switch path for native tasks using the entry trampoline.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
(cherry picked from commit 18011eac28c7cb31c87b86b7d0e5b01894405c7f)

[toddpoynor@google.com: fixup context]
Change-Id: I4a0ded2e339b0c75521bc3b5a7fbbb3e60aa8774
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Git-commit: da1016a5
Git-repo: https://android.googlesource.com/kernel/common/


Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>