include: arch: arm64: limits header needed for ASSERT

Cited commit requires the limits.h header to fetch the defintion of
INT_MAX, which is missing today. The build process fails without it.

Fixes: cb5c5519e4 ("arch/arm64: Support runtime frequency")
Signed-off-by: Rodrigo Cataldo <rodrigo.cataldo@huawei.com>
Co-authored-by: Henri Xavier <datacomos@huawei.com>