isl_aff.c: pw_multi_aff_from_map_stride: fix typo in code
isl_aff.c: pw_multi_aff_from_map_stride: fix typo in code

We were applying isl_pw_multi_aff_from_map to the wrong
variable.  The value of this variable is always
the same as that of the correct variable since the set
is modified in place.

Detected by a scan_build on Polly.

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

inducer/isl-mirror,crossbuild/isl,tobig/isl,simbuerg/isl,KangDroidSMProject/ISL,simbuerg/isl,UBERTC/isl,abduld/isl,BenzoSM/isl,PollyLabs/isl,SaberMod/isl-current,evaautomation/isl,inducer/isl-mirror,evaautomation/isl,SaberMod/isl-current,BenzoSM/isl,inducer/isl-mirror,evaautomation/isl,tobig/isl,tobig/isl,Distrotech/isl,nicolasvasilache/isl,inducer/isl-mirror,nicolasvasilache/isl,nicolasvasilache/isl,KangDroidSMProject/ISL,tobig/isl,SaberMod/isl-current,KangDroidSMProject/ISL,evaautomation/isl,simbuerg/isl,nicolasvasilache/isl,PollyLabs/isl,SaberMod/isl-current,Distrotech/isl,BenzoSM/isl,Meinersbur/isl,crossbuild/isl,PollyLabs/isl,Distrotech/isl,abduld/isl,crossbuild/isl,PollyLabs/isl,crossbuild/isl,KangDroidSMProject/ISL,Meinersbur/isl,BenzoSM/isl,PollyLabs/isl,nicolasvasilache/isl,abduld/isl,Distrotech/isl,BenzoSM/isl,simbuerg/isl,Meinersbur/isl,Meinersbur/isl,simbuerg/isl,UBERTC/isl,KangDroidSMProject/ISL,Distrotech/isl,abduld/isl,UBERTC/isl,UBERTC/isl,inducer/isl-mirror