[PATCH v3 16/19] riscv32: Specify the arch_minimum_kernel as 5.4

[Maciej W. Rozycki]

On Wed, 15 Jul 2020, Maciej W. Rozycki wrote:

>  Otherwise OK.

 Also I suggest reordering this change and the next ahead of 15/19, so 
that the tree is consistent at the point RV32 builds are enabled with the 
removal of the trap from `sysdeps/riscv/preconfigure'.

  Maciej