Config.in: disable PIC/PIE for Nios2

Config.in: disable PIC/PIE for Nios2

Recently in Buildroot the option BR2_PIC_PIE has been enabled by default along
with other hardening features [1]. Since then the nios2 defconfig
qemu_nios2_10m50_defconfig is failing to boot due to a segfault in init program:

Run /init as init process
  with arguments:
    /init
  with environment:
    HOME=/
    TERM=linux
Failed to execute /init (error -12)

See Buildroot build log and Qemu runtime test log in build artifacts [2].

Analyzing one of the binary with strace show that the problem occur
very early when starting the new process:

 # strace ./busybox
 execve("./busybox", ["./busybox"], 0x7f91ce90 /* 10 vars */) = -1 ENOMEM
(Cannot allocate memory)
 +++ killed by SIGSEGV +++

Several binutils/glibc/gcc version has been tested without any success.

The issue has been reported to the glibc mailing list but it can be a linker
or kernel bug [3].

For the Buildroot 2021.05 release, disable BR2_PIC_PIE until the problem is
found and fixed.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/1285145889

[1] https://git.buildroot.net/buildroot/commit/?id=810ba387bec3c5b6904e8893fb4cb6f9d3717466
[2] https://gitlab.com/buildroot.org/buildroot/-/jobs/1285145889
[3] https://sourceware.org/pipermail/libc-alpha/2021-May/126912.html

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>