FROMLIST: [PATCH 1/6] arm64: compat: Use vDSO sigreturn trampolines if available

(cherry pick from url https://patchwork.kernel.org/patch/10060449/

)

If the compat vDSO is enabled, it replaces the sigreturn page.
Therefore, we use the sigreturn trampolines the vDSO provides instead.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Bug: 63737556
Bug: 20045882
Change-Id: Ic0933741e321e1bf66409b7e190a776f12948024
Signed-off-by: khusika <khusikadhamar@gmail.com>