x86/hyperv: Do not move the original assembly code in hv_do_hypercall()

Add a return for hv_isolation_type_en_snp() to avoid moving the code unnecessarily

Fixes: 21ff4de070a7 ("x86/hyperv: Use vmmcall to implement Hyper-V hypercall in sev-snp enlightened guest")
Link: lantianyu/linux@21ff4de
Signed-off-by: Dexuan Cui <decui@microsoft.com>

arch/x86/include/asm/mshyperv.h

@@ -73,18 +73,19 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
 				       "+c" (control), "+d" (input_address)
 				     :  "r" (output_address)
 				     : "cc", "memory", "r8", "r9", "r10", "r11");
-	} else {
-		if (!hv_hypercall_pg)
-			return U64_MAX;
-
-		__asm__ __volatile__("mov %4, %%r8\n"
-				     CALL_NOSPEC
-				     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
-				       "+c" (control), "+d" (input_address)
-				     :  "r" (output_address),
-					THUNK_TARGET(hv_hypercall_pg)
-				     : "cc", "memory", "r8", "r9", "r10", "r11");
+		return hv_status;
 	}
+
+	if (!hv_hypercall_pg)
+		return U64_MAX;
+
+	__asm__ __volatile__("mov %4, %%r8\n"
+			     CALL_NOSPEC
+			     : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+			       "+c" (control), "+d" (input_address)
+			     :  "r" (output_address),
+				THUNK_TARGET(hv_hypercall_pg)
+			     : "cc", "memory", "r8", "r9", "r10", "r11");
 #else
 	u32 input_address_hi = upper_32_bits(input_address);
 	u32 input_address_lo = lower_32_bits(input_address);