cacheinfo: Remove unused check in init_cache_level()

cacheinfo: Remove unused check in init_cache_level()

commit e75d18cecbb3 ("arm64: cacheinfo: Fix incorrect assignment
of signed error value to unsigned fw_level")
checks the fw_level value in init_cache_level() in case the value is
negative.
Remove this check as the error code is not returned through
fw_level anymore, and reset fw_level if acpi_get_cache_info()
failed. This allows to try fetching the cache information from
clidr_el1.

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Link: https://lore.kernel.org/r/20230124154053.355376-4-pierre.gondois@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>