riscv: Fix Kendryte K210 device tree

riscv: Fix Kendryte K210 device tree

The Kendryte K210 SoC CLINT is compatible with Sifive clint v0
(sifive,clint0). Fix the Kendryte K210 device tree clint entry to be
inline with the sifive timer definition documented in
Documentation/devicetree/bindings/timer/sifive,clint.yaml.
The device tree clint entry is renamed similarly to u-boot device tree
definition to improve compatibility with u-boot defined device tree.
To ensure correct initialization, the interrup-cells attribute is added
and the interrupt-extended attribute definition fixed.

This fixes boot failures with Kendryte K210 SoC boards.

Note that the clock referenced is kept as K210_CLK_ACLK, which does not
necessarilly match the clint MTIME increment rate. This however does not
seem to cause any problem for now.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>