MAINTAINERS: SXGBE authors update

The mail address for Siva Reddy Kallam is bouncing, remove the email
address from the MAINTAINERS entry for Samsung's SXGBE driver.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -7674,7 +7674,6 @@ F:	drivers/clk/samsung/
 SAMSUNG SXGBE DRIVERS
 M:	Byungho An <bh74.an@samsung.com>
 M:	Girish K S <ks.giri@samsung.com>
-M:	Siva Reddy Kallam <siva.kallam@samsung.com>
 M:	Vipul Pandya <vipul.pandya@samsung.com>
 S:	Supported
 L:	netdev@vger.kernel.org