MAINTAINERS: Include the TI docs under ARM TI

Add entry for the TI boards documentation under ARM TI

Reviewed-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Dhruva Gole <d-gole@ti.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index ddcb712..f1fe19e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -732,6 +732,7 @@
 F:	arch/arm/include/asm/arch-omap*/
 F:	arch/arm/include/asm/ti-common/
 F:	board/ti/
+F:	doc/board/ti/
 F:	drivers/dma/ti*
 F:	drivers/dma/ti*/
 F:	drivers/firmware/ti_sci.*