x86/boot/e820: Fix typo in e820.c comment

change "itsmain" to "its main".

Fixes: 544a0f4 ("x86/boot/e820: Rename e820_table_saved to e820_table_firmware and improve the description")
Signed-off-by: Wang Yong <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Wang Yong

arch/x86/kernel/e820.c

@@ -53,7 +53,7 @@
  *
  * Once the E820 map has been converted to the standard Linux memory layout
  * information its role stops - modifying it has no effect and does not get
- * re-propagated. So itsmain role is a temporary bootstrap storage of firmware
+ * re-propagated. So its main role is a temporary bootstrap storage of firmware
  * specific memory layout data during early bootup.
  */
 static struct e820_table e820_table_init		__initdata;