x86, doc: fix references to Documentation/x86/i386/boot.txt

Impact: Documentation fix

The amazing dancing boot.txt file has jumped places again.  It should
never have been in Documentation/x86/i386, since it never was
32-bit-specific, but it unfortunately ended up there for a while.
Signed-off-by: NKyle McMartin <kyle@redhat.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Documentation/kernel-parameters.txt

@@ -114,7 +114,7 @@ In addition, the following text indicates that the option:
 Parameters denoted with BOOT are actually interpreted by the boot
 loader, and have no meaning to the kernel directly.
 Do not modify the syntax of boot loader parameters without extreme
-need or coordination with <Documentation/x86/i386/boot.txt>.
+need or coordination with <Documentation/x86/boot.txt>.
 
 There are also arch-specific kernel-parameters not documented here.
 See for example <Documentation/x86/x86_64/boot-options.txt>.
@@ -2449,7 +2449,7 @@ and is between 256 and 4096 characters. It is defined in the file
 			See Documentation/fb/modedb.txt.
 
 	vga=		[BOOT,X86-32] Select a particular video mode
-			See Documentation/x86/i386/boot.txt and
+			See Documentation/x86/boot.txt and
 			Documentation/svga.txt.
 			Use vga=ask for menu.
 			This is actually a boot loader parameter; the value is