cifs-utils: unconditionally disable PIE

cifs-utils: unconditionally disable PIE

PIE support in Buildroot should be enabled via the global option
BR2_RELRO_FULL option, and not done on a per-package basis, therefore
PIE should unconditionally be disabled in the cifs-utils package.

This has the added side-effect that it works around a binutils bug on
SPARC causing the linker to segfault when PIE is enabled:

sparc-linux-gcc -Wall -Wextra -D_FORTIFY_SOURCE=2 -fpie -pie -Wl,-z,relro,-z,now -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64  -Os    -o mount.cifs mount.cifs.o mtab.o resolve_host.o util.o  -lcap-ng
collect2: fatal error: ld terminated with signal 6 [Aborted], core dumped

This issue will reappear when we start testing BR2_RELRO_FULL in the
autobuilders, but in the mean time it avoids the problem.

Fixes:

  http://autobuild.buildroot.net/results/a5342890f39bdccae1324e7d3dbe0eab1aad28e5/

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