cifs-utils: fix building on static

Disable position independent executables when building on static.

Fixes:
   http://autobuild.buildroot.net/results/bb0/bb00db98477f0f81c95ac1830ef3649b30963416/



Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>