MAINTAINERS: Add Vignesh to TI K3 platform maintainership

Add Vignesh to TI K3 platform maintainership. We will rotate roles for
each kernel version to help spread the work load a little better.

Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20210915121308.26795-1-nm@ti.com'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

MAINTAINERS

@@ -2713,6 +2713,7 @@ F:	drivers/power/reset/keystone-reset.c
 
 ARM/TEXAS INSTRUMENTS K3 ARCHITECTURE
 M:	Nishanth Menon <nm@ti.com>
+M:	Vignesh Raghavendra <vigneshr@ti.com>
 M:	Tero Kristo <kristo@kernel.org>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 S:	Supported