powerpc/fadump: Update comment about offset where fadump is reserved

With commit f6e6bedb7731 ("powerpc/fadump: Reserve memory at an offset
closer to bottom of RAM"), memory for fadump is no longer reserved at
the top of RAM. But there are still a few places which say so. Change
them appropriately.

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/Documentation/powerpc/firmware-assisted-dump.txt b/Documentation/powerpc/firmware-assisted-dump.txt
index 9cabaf8..bdd344a 100644
--- a/Documentation/powerpc/firmware-assisted-dump.txt
+++ b/Documentation/powerpc/firmware-assisted-dump.txt
@@ -61,8 +61,8 @@
          boot successfully. For syntax of crashkernel= parameter,
          refer to Documentation/kdump/kdump.txt. If any offset is
          provided in crashkernel= parameter, it will be ignored
-         as fadump reserves memory at end of RAM for boot memory
-         dump preservation in case of a crash.
+         as fadump uses a predefined offset to reserve memory
+         for boot memory dump preservation in case of a crash.
 
 -- After the low memory (boot memory) area has been saved, the
    firmware will reset PCI and other hardware state.  It will