arm64: compat: Remove leftover variable declaration

arm64: compat: Remove leftover variable declaration

Commit a1d5ebaf8ccd ("arm64: big-endian: don't treat code as data when
copying sigret code") moved the 32-bit sigreturn trampoline code from
the aarch32_sigret_code array to kuser32.S. The commit removed the
array definition from signal32.c, but not its declaration in
signal32.h. Remove the leftover declaration.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
(cherry picked from commit 82d24d114f249d919b918ff8eefde4117db8f088)

CVE-2017-5753
CVE-2017-5715
CVE-2017-5754

Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>