[Qemu-trivial] [PATCH v2 2/2] docs/memory.txt: Fix document on MMIO operations

[Fam Zheng]

.impl.valid should be .impl.unaligned and the description needs some
fixes.

Signed-off-by: Fam Zheng <address@hidden>
---
 docs/memory.txt | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/docs/memory.txt b/docs/memory.txt
index d5abc92..4c7bc43 100644
--- a/docs/memory.txt
+++ b/docs/memory.txt
@@ -232,7 +232,8 @@ various constraints can be supplied to control how these 
callbacks are called:
    (in bytes) supported by the *implementation*; other access sizes will be
    emulated using the ones available. For example a 4-byte write will be
    emulated using four 1-byte writes, if .impl.max_access_size = 1.
- - .impl.valid specifies that the *implementation* only supports unaligned
-   accesses; unaligned accesses will be emulated by two aligned accesses.
+ - .impl.unaligned specifies that the *implementation* supports unaligned
+   accesses; if false, an unaligned access will be emulated by two aligned
+   accesses.
  - .old_mmio can be used to ease porting from code using
    cpu_register_io_memory(). It should not be used in new code.
-- 
1.9.2