arm64: efi: Don't include EFI fpsimd save/restore code in non-EFI kernels

__efi_fpsimd_begin()/__efi_fpsimd_end() are for use when making EFI
calls only, so using them in non-EFI kernels is not allowed.

This patch compiles them out if CONFIG_EFI is not set.
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/kernel/fpsimd.c

@@ -321,6 +321,8 @@ void kernel_neon_end(void)
 }
 EXPORT_SYMBOL(kernel_neon_end);
 
+#ifdef CONFIG_EFI
+
 static DEFINE_PER_CPU(struct fpsimd_state, efi_fpsimd_state);
 static DEFINE_PER_CPU(bool, efi_fpsimd_state_used);
 
@@ -370,6 +372,8 @@ void __efi_fpsimd_end(void)
 		kernel_neon_end();
 }
 
+#endif /* CONFIG_EFI */
+
 #endif /* CONFIG_KERNEL_MODE_NEON */
 
 #ifdef CONFIG_CPU_PM