x86: fix CONFIG_NONPROMISC_DEVMEM prompt and help text

Here is an attempt to translate the prompt and help text into something
which is legible and, as a bonus, correct.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/Kconfig.debug

@@ -6,15 +6,19 @@ config TRACE_IRQFLAGS_SUPPORT
 source "lib/Kconfig.debug"
 
 config NONPROMISC_DEVMEM
-	bool "Disable promiscuous /dev/mem"
+	bool "Filter access to /dev/mem"
 	help
-	  The /dev/mem file by default only allows userspace access to PCI
-	  space and the BIOS code and data regions. This is sufficient for
-	  dosemu and X and all common users of /dev/mem. With this config
-	  option, you allow userspace access to all of memory, including
-	  kernel and userspace memory. Accidental access to this is
-	  obviously disasterous, but specific access can be used by people
-	  debugging the kernel.
+	  If this option is left off, you allow userspace access to all
+	  of memory, including kernel and userspace memory. Accidental
+	  access to this is obviously disastrous, but specific access can
+	  be used by people debugging the kernel.
+
+	  If this option is switched on, the /dev/mem file only allows
+	  userspace access to PCI space and the BIOS code and data regions.
+	  This is sufficient for dosemu and X and all common users of
+	  /dev/mem.
+
+	  If in doubt, say Y.
 
 config EARLY_PRINTK
 	bool "Early printk" if EMBEDDED