starfive: disable BTRFS(will trigger a link error with *some* RV64 GCC)[will be merged]
This patch just disable BTRFS on RISC-V.
Because BTRFS will select ZSTD which will trigger a link error with
*some* RV64 GCC:
---
riscv64-unknown-linux-gnu-ld.bfd: /usr/lib/gcc/riscv64-unknown-linux-gnu/11.2.0/libgcc.a(_clzsi2.o): can't link double-float modules with soft-float modules
riscv64-unknown-linux-gnu-ld.bfd: failed to merge target specific data of file /usr/lib/gcc/riscv64-unknown-linux-gnu/11.2.0/libgcc.a(_clzsi2.o)
riscv64-unknown-linux-gnu-ld.bfd: /usr/lib/gcc/riscv64-unknown-linux-gnu/11.2.0/libgcc.a(_clz.o): can't link double-float modules with soft-float modules
riscv64-unknown-linux-gnu-ld.bfd: failed to merge target specific data of file /usr/lib/gcc/riscv64-unknown-linux-gnu/11.2.0/libgcc.a(_clz.o)
make: *** [Makefile:1787: u-boot] Error 1
---
Notice: RV64 GCC on Fedora works well with enabling BTRFS.