x86: rename KERNEL_TEXT_SIZE => KERNEL_IMAGE_SIZE

The KERNEL_TEXT_SIZE constant was mis-named, as we not only map the kernel
text but data, bss and init sections as well.

That name led me on the wrong path with the KERNEL_TEXT_SIZE regression,
because i knew how big of _text_ my images have and i knew about the 40 MB
"text" limit so i wrongly thought to be on the safe side of the 40 MB limit
with my 29 MB of text, while the total image size was slightly above 40 MB.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index b037b15..a007454 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -393,7 +393,7 @@
 	 *  too.)
 	 */
 	PMDS(0, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL,
-		KERNEL_TEXT_SIZE/PMD_SIZE)
+		KERNEL_IMAGE_SIZE/PMD_SIZE)
 
 NEXT_PAGE(level2_spare_pgt)
 	.fill   512, 8, 0