riscv: Using TOOLCHAIN_HAS_ZIHINTPAUSE marco replace zihintpause

Actually it is a part of Conor's
commit aae538cd ("riscv: fix detection of toolchain
Zihintpause support").
It is looks like a merge issue. Samuel's
commit 0b1d60d6

 ("riscv: Fix build with
CONFIG_CC_OPTIMIZE_FOR_SIZE=y") do not base on Conor's commit and
revert to __riscv_zihintpause. So this patch can fix it.

Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
Fixes: 3c349eac

 ("Merge patch "riscv: Fix build with CONFIG_CC_OPTIMIZE_FOR_SIZE=y"")
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230802064215.31111-1-minda.chen@starfivetech.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>