riscv: global_data.h: Correct the comment for PLICSW

PLIC is used for external interrupt, while PLICSW is an Andes-specific
design for software interrupt.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Rick Chen <rick@andestech.com>
1 file changed