arm64: dts: apple: t7000: Add missing CPU p-state 7 for J96 and J97

Add missing CPU p-state 7 @ 1512 MHz for iPad mini 4.

Fixes: e9732399 ("arm64: dts: apple: t7000: Add cpufreq nodes")
Signed-off-by: Nick Chan <towinchenmi@gmail.com>
Link: https://lore.kernel.org/r/20250217-mini4-cpufreq-v1-1-8974e90dd806@gmail.com


Signed-off-by: Sven Peter <sven@svenpeter.dev>