x86/acrn: Remove redundant chars from ACRN signature

hypervisor_cpuid_base() only handles 12 chars of the hypervisor
signature string but is provided with 14 chars.

Remove the redundancy. Additionally, replace the user space uint32_t
with preferred kernel type u32.
Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20200806114111.9448-1-shuo.a.liu@intel.com

arch/x86/kernel/cpu/acrn.c

@@ -17,9 +17,9 @@
 #include <asm/idtentry.h>
 #include <asm/irq_regs.h>
 
-static uint32_t __init acrn_detect(void)
+static u32 __init acrn_detect(void)
 {
-	return hypervisor_cpuid_base("ACRNACRNACRN\0\0", 0);
+	return hypervisor_cpuid_base("ACRNACRNACRN", 0);
 }
 
 static void __init acrn_init_platform(void)