arm64/sve: Remove unused declaration read_smcr_features()

Commit 39120848 ("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.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/include/asm/fpsimd.h

@@ -155,8 +155,6 @@ extern void cpu_enable_sme2(const struct arm64_cpu_capabilities *__unused);
 extern void cpu_enable_fa64(const struct arm64_cpu_capabilities *__unused);
 extern void cpu_enable_fpmr(const struct arm64_cpu_capabilities *__unused);
 
-extern u64 read_smcr_features(void);
-
 /*
  * Helpers to translate bit indices in sve_vq_map to VQ values (and
  * vice versa).  This allows find_next_bit() to be used to find the