dt-bindings: clock: keystone: remove unstable remark

Keystone clock controller bindings were marked as work-in-progress /
unstable in 2013 in commit b9e0d40c0d83 ("clk: keystone: add Keystone
PLL clock driver") and commit 7affe5685c96 ("clk: keystone: Add gate
control clock driver") Almost eleven years is enough, so drop the
"unstable" remark and expect usual ABI rules.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Acked-by: Stephen Boyd <[e-mail]>
Acked-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring <[e-mail]>

Documentation/devicetree/bindings/clock/keystone-gate.txt

···
-Status: Unstable - ABI compatibility may be broken in the future
-
 Binding for Keystone gate control driver which uses PSC controller IP.
 
 This binding uses the common clock binding[1].

Documentation/devicetree/bindings/clock/keystone-pll.txt

···
-Status: Unstable - ABI compatibility may be broken in the future
-
 Binding for keystone PLLs. The main PLL IP typically has a multiplier,
 a divider and a post divider. The additional PLL IPs like ARMPLL, DDRPLL
 and PAPLL are controlled by the memory mapped register where as the Main