x86: Kconfig: MARK_GRAPHICS_MEM_WRCOMB cosmetics

Remove the ending period of the MARK_GRAPHICS_MEM_WRCOMB option. Also
fix the indention of its help text.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/x86/Kconfig

@@ -181,12 +181,12 @@ config X86_RAMTEST
 	  detecting obvious failures.
 
 config MARK_GRAPHICS_MEM_WRCOMB
-	bool "Mark graphics memory as write-combining."
+	bool "Mark graphics memory as write-combining"
 	default n
 	help
-	 The graphics performance may increase if the graphics
-	 memory is set as write-combining cache type. This option
-	 enables marking the graphics memory as write-combining.
+	  The graphics performance may increase if the graphics
+	  memory is set as write-combining cache type. This option
+	  enables marking the graphics memory as write-combining.
 
 menu "Display"