riscv: Rename Andes cpu and board names

The current ae350-related defconfigs could also
support newer Andes CPU IP, so modify the names of CPU
from ax25 to andesv5, and board name from ax25-ae350 to ae350.

Signed-off-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/configs/ae350_rv32_spl_defconfig b/configs/ae350_rv32_spl_defconfig
index 4d3623a..d61f7f5 100644
--- a/configs/ae350_rv32_spl_defconfig
+++ b/configs/ae350_rv32_spl_defconfig
@@ -8,7 +8,7 @@
 CONFIG_SPL_SYS_MALLOC_F_LEN=0x100000
 CONFIG_SPL=y
 CONFIG_SYS_LOAD_ADDR=0x100000
-CONFIG_TARGET_AX25_AE350=y
+CONFIG_TARGET_AE350=y
 CONFIG_RISCV_SMODE=y
 # CONFIG_AVAILABLE_HARTS is not set
 CONFIG_DISTRO_DEFAULTS=y