doc: fix wrong arch/i386 references

Change all "arch/i386" to "arch/x86" in Documentaion/,
since the directory has changed.

Also update the files which have changed their filename
in the meantime accordingly.

Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
[jkosina@suse.cz: reword changelog]
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/Documentation/mca.txt b/Documentation/mca.txt
index 510375d..dfd130c 100644
--- a/Documentation/mca.txt
+++ b/Documentation/mca.txt
@@ -11,7 +11,7 @@
 
 The ideal MCA adapter detection is done through the use of the
 Programmable Option Select registers.  Generic functions for doing
-this have been added in include/linux/mca.h and arch/i386/kernel/mca.c.
+this have been added in include/linux/mca.h and arch/x86/kernel/mca_32.c.
 Everything needed to detect adapters and read (and write) configuration
 information is there.  A number of MCA-specific drivers already use
 this.  The typical probe code looks like the following:
@@ -81,7 +81,7 @@
 In general, an interrupt must be acknowledged not only at the ICU (which
 is done automagically by the kernel), but at the device level.  In
 particular, IRQ 0 must be reset after a timer interrupt (now done in
-arch/i386/kernel/time.c) or the first timer interrupt hangs the system.
+arch/x86/kernel/time.c) or the first timer interrupt hangs the system.
 There were also problems with the 1.3.x floppy drivers, but that seems
 to have been fixed.