arm64/sve: Remove unused declaration read_smcr_features()

arm64/sve: Remove unused declaration read_smcr_features()

Commit 391208485c3a ("arm64/sve: Remove SMCR pseudo register from cpufeature code")
removed the implementation but leave declaration.

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20240810093944.2587809-1-yuehaibing@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>