isl_band_tile: set parent field of the child band
isl_band_tile: set parent field of the child band

The original code would leave it pointing to the parent of the original
band, i.e., the grandparent of the child band.

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

VanirLLVM/toolchain_isl,inducer/isl-mirror,epowers/isl,PollyLabs/isl,simbuerg/isl,jleben/isl,nicolasvasilache/isl,epowers/isl,crossbuild/isl,BobSaget-Mod/libisl,PollyLabs/isl,BobSaget-Mod/libisl,KangDroidSMProject/ISL,SaberMod/isl-current,nicolasvasilache/isl,SaberMod/isl-current,serge-sans-paille/isl,BenzoSM/isl,PollyLabs/isl,BenzoSM/isl,UBERTC/isl,BobSaget-Mod/libisl,cfx-next/toolchain_isl-upstream,jleben/isl,VanirLLVM/toolchain_isl,simbuerg/isl,serge-sans-paille/isl,inducer/isl-mirror,Meinersbur/isl,Meinersbur/isl,cfx-next/toolchain_isl-upstream,evaautomation/isl,jleben/isl,jleben/isl,Distrotech/isl,serge-sans-paille/isl,serge-sans-paille/isl,KangDroidSMProject/ISL,BenzoSM/isl,abduld/isl,UBERTC/isl,VanirLLVM/toolchain_isl,BobSaget-Mod/libisl,inducer/isl-mirror,Distrotech/isl,SaberMod/isl-current,nicolasvasilache/isl,abduld/isl,KangDroidSMProject/ISL,cfx-next/toolchain_isl-upstream,UBERTC/isl,crossbuild/isl,SaberMod/isl-current,crossbuild/isl,abduld/isl,evaautomation/isl,KangDroidSMProject/ISL,Meinersbur/isl,nicolasvasilache/isl,epowers/isl,UBERTC/isl,Distrotech/isl,simbuerg/isl,tobig/isl,tobig/isl,inducer/isl-mirror,VanirLLVM/toolchain_isl,Meinersbur/isl,tobig/isl,BenzoSM/isl,crossbuild/isl,KangDroidSMProject/ISL,epowers/isl,cfx-next/toolchain_isl-upstream,evaautomation/isl,nicolasvasilache/isl,abduld/isl,Distrotech/isl,serge-sans-paille/isl,Distrotech/isl,jleben/isl,PollyLabs/isl,BobSaget-Mod/libisl,VanirLLVM/toolchain_isl,inducer/isl-mirror,BenzoSM/isl,tobig/isl,cfx-next/toolchain_isl-upstream,evaautomation/isl,PollyLabs/isl,simbuerg/isl,epowers/isl,simbuerg/isl