Compilation fails without CONFIG_RISCV_NONSTANDARD_CACHE_OPS

[caseif]

Compilation of the kernel fails during linking on my system due to an undefined reference in drivers/gpu/drm/starfive/starfive_drm_vpp.c to function sifive_ccache_flush_range, which is implemented in drivers/soc/sifive/sifive_ccache.c. This implementation is guarded by a preprocessor check for the CONFIG_RISCV_NONSTANDARD_CACHE_OPS option, but the call in starfive_drm_vpp.c is not thus causing the undefined reference error.

I'm not super versed in driver/kernel development so I won't speculate on the underlying reasoning for conditional compilation, but I suspect that the call to the function should probably be ifdef-guarded given that its implementation is guarded. Adding a guard or setting the option both result in successful compilation.

[esmil]

This should be fixed in the latest version of the visionfive branch.