treewide: Fix Marek's name and change my e-mail address

Fix diacritics in some instances of my name and change my e-mail address
to kabel@kernel.org.

Add corresponding .mailmap entries.

Signed-off-by: Marek BehĂșn <kabel@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/fs/btrfs/extent-io.c b/fs/btrfs/extent-io.c
index 774e29e..f4d56a0 100644
--- a/fs/btrfs/extent-io.c
+++ b/fs/btrfs/extent-io.c
@@ -2,7 +2,7 @@
 /*
  * BTRFS filesystem implementation for U-Boot
  *
- * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
+ * 2017 Marek Behún, CZ.NIC, kabel@kernel.org
  */
 
 #include <linux/kernel.h>