clk: sunxi-ng: h6: Fix default PLL GPU rate

clk: sunxi-ng: h6: Fix default PLL GPU rate

In commit 4167ac8a657e ("clk: sunxi-ng: sun50i: h6: Modify GPU clock
configuration to support DFS") divider M0 was forced to be 1 in order to
support DFS. However, that left N as it is, at high value of 36. On
boards without devfreq enabled (all of them in kernel 6.0), this
effectively sets GPU frequency to 864 MHz. This is about 100 MHz above
maximum supported frequency.

In order to fix this, let's set N to 18 (register value 17). That way
default frequency of 432 MHz is preserved.

Fixes: 4167ac8a657e ("clk: sunxi-ng: sun50i: h6: Modify GPU clock configuration to support DFS")
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220928200122.3963509-1-jernej.skrabec@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>