MAINTAINERS: Fix mail

Sam doesn't work for Linaro anymore, so Linaro mail is not valid. Change
it to his home mail instead.

Signed-off-by: Sam Protsenko <joe.skb7@gmail.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index 438fb22..7d2729d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -52,7 +52,7 @@
 		-----------------------------------
 ANDROID AB
 M:	Igor Opaniuk <igor.opaniuk@gmail.com>
-R:	Sam Protsenko <semen.protsenko@linaro.org>
+R:	Sam Protsenko <joe.skb7@gmail.com>
 S:	Maintained
 F:	cmd/ab_select.c
 F:	common/android_ab.c