arm64: topology: fix possible overflow in amu_fie_setup()

cpufreq_get_hw_max_freq() returns max frequency in kHz as *unsigned int*,
while freq_inv_set_max_ratio() gets passed this frequency in Hz as 'u64'.
Multiplying max frequency by 1000 can potentially result in overflow --
multiplying by 1000ULL instead should avoid that...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Fixes: cd0ed03a

 ("arm64: use activity monitors for frequency invariance")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/01493d64-2bce-d968-86dc-11a122a9c07d@omp.ru
Signed-off-by: Will Deacon <will@kernel.org>