arm64: kasan: remove !KASAN_VMALLOC remnants

arm64: kasan: remove !KASAN_VMALLOC remnants

Historically, KASAN could be selected with or without KASAN_VMALLOC, but
since commit:

  f6f37d9320a11e90 ("arm64: select KASAN_VMALLOC for SW/HW_TAGS modes")

... we can never select KASAN without KASAN_VMALLOC on arm64, and thus
arm64 code for KASAN && !KASAN_VMALLOC is redundant and can be removed.

Remove the redundant code kasan_init.c

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will@kernel.org>
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com>
Link: https://lore.kernel.org/r/20230530110328.2213762-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>