MAINTAINERS: update Aijun Sun's email address

Spreadtrum has become Unisoc. Update Aijun's email accordingly.

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Aijun Sun <aijun.sun@unisoc.com>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index 47fd059..74665b0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -166,7 +166,7 @@
 F:	core/arch/arm/plat-synquacer/
 
 Spreadtrum SC9860
-R:	Aijun Sun <aijun.sun@spreadtrum.com>
+R:	Aijun Sun <aijun.sun@unisoc.com>
 R:	[@OP-TEE/plat-sprd]
 S:	Maintained
 F:	core/arch/arm/plat-sprd/