Update isa.c

fix the spaces to tab at line 50 to fix indenting issue.

src/x86/isa.c

diff --git a/src/x86/isa.c b/src/x86/isa.c
index 7f466b7..377583b 100644
--- a/src/x86/isa.c
+++ b/src/x86/isa.c
@@ -47,7 +47,7 @@
 	const struct cpuid_regs structured_feature_info1 =
 		(max_base_index >= 7) ? cpuidex(7, 1) : (struct cpuid_regs){0, 0, 0, 0};
 	const struct cpuid_regs structured_feature_info2 =
-	    (max_base_index >= 7) ? cpuidex(0x24, 0) : (struct cpuid_regs){0, 0, 0, 0};
+		(max_base_index >= 7) ? cpuidex(0x24, 0) : (struct cpuid_regs){0, 0, 0, 0};
 
 	const uint32_t processor_capacity_info_index = UINT32_C(0x80000008);
 	const struct cpuid_regs processor_capacity_info = (max_extended_index >= processor_capacity_info_index)