MAINTAINERS: Update maintainer information for Altera Triple Speed Ethernet Driver

The previous maintainer, Joyce Ooi, is no longer with the company,
and her email is no longer reachable. As a result, the maintainer
information for the Altera Triple Speed Ethernet Driver has been updated.

Changes:
- Replaced Joyce Ooi's email with Boon Khai Ng's email address.
- Kept the component's status as "Maintained".

Signed-off-by: Boon Khai Ng <boon.khai.ng@altera.com>
Link: https://patch.msgid.link/20250825071321.30131-1-boon.khai.ng@altera.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: ngboonkhai

MAINTAINERS

@@ -937,7 +937,7 @@ S:	Maintained
 F:	drivers/gpio/gpio-altera.c
 
 ALTERA TRIPLE SPEED ETHERNET DRIVER
-M:	Joyce Ooi <joyce.ooi@intel.com>
+M:	Boon Khai Ng <boon.khai.ng@altera.com>
 L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ethernet/altera/