x86/boot: Save several bytes in decompressor

gdt64 represents the content of GDTR under x86-64, which actually needs
10 bytes only, ".long" & ".word" is superfluous.

Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <bp@alien8.de>
Cc: <hpa@zytor.com>
Link: https://lkml.kernel.org/r/20190123100014.23721-1-caoj.fnst@cn.fujitsu.com

arch/x86/boot/compressed/head_64.S

@@ -645,8 +645,6 @@ no_longmode:
 	.data
 gdt64:
 	.word	gdt_end - gdt
-	.long	0
-	.word	0
 	.quad   0
 gdt:
 	.word	gdt_end - gdt