RISC-V: Fix bootstrap failure.
gcc/
PR bootstrap/84856
* config/riscv/riscv.c (riscv_function_arg_boundary): Use
PREFERRED_STACK_BOUNDARY instead of STACK_BOUNDARY.
(riscv_first_stack_step): Likewise.
(riscv_option_override): Use STACK_BOUNDARY instead of
MIN_STACK_BOUNDARY.
* config/riscv/riscv.h (STACK_BOUNDARY): Renamed from
MIN_STACK_BOUNDARY.
(BIGGEST_ALIGNMENT): Set to 128.
(PREFERRED_STACK_BOUNDARY): Renamed from STACK_BOUNDARY.
(RISCV_STACK_ALIGN): Use PREFERRED_STACK_BOUNDARY instead of
STACK_BOUNDARY.
From-SVN: r258650