support/config-fragments/autobuild: fix SSP in br-nios2-glibc

support/config-fragments/autobuild: fix SSP in br-nios2-glibc

Commit c8680956819fae8776d7bd6d1f0e67a7b6436672 ("toolchain: fix
detection of SSP support") fixed the SSP check so that it does the
correct thing for nios2 toolchains. While this commit fixed the
description of the Sourcery NIOSII toolchain, it didn't fix the
description for the autobuilders of the br-nios2-glibc toolchain,
causing some build failures. This commit adjusts br-nios2-glibc.config
to indicate that the toolchain doesn't have SSP support.

Fixes:

  http://autobuild.buildroot.net/results/6c44e328b7bffd8474d29d5bdf1ea109ec15f4ad/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>