MAINTAINERS: change ENA driver maintainers email domain

ENA driver was developed by developers from Annapurna Labs.
Annapurna Labs was acquired by Amazon and the company's domain
(@annapurnalabs.com) will become deprecated soon.

Update the email addresses of the maintainers to the alternative amazon
emails (@amazon.com)

Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -700,9 +700,9 @@ F:	include/linux/altera_uart.h
 F:	include/linux/altera_jtaguart.h
 
 AMAZON ETHERNET DRIVERS
-M:	Netanel Belgazal <netanel@annapurnalabs.com>
-R:	Saeed Bishara <saeed@annapurnalabs.com>
-R:	Zorik Machulsky <zorik@annapurnalabs.com>
+M:	Netanel Belgazal <netanel@amazon.com>
+R:	Saeed Bishara <saeedb@amazon.com>
+R:	Zorik Machulsky <zorik@amazon.com>
 L:	netdev@vger.kernel.org
 S:	Supported
 F:	Documentation/networking/ena.txt