x86, setup: guard against pre-ACPI 3 e820 code not updating %ecx
x86, setup: guard against pre-ACPI 3 e820 code not updating %ecx

Impact: BIOS bug safety

For pre-ACPI 3 BIOSes, pre-initialize the end of the e820 buffer just
in case the BIOS returns an unchanged %ecx but without actually
touching the ACPI 3 extended flags field.

Signed-off-by: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@zytor.com>

KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas