MAINTAINERS: Add myself as reviewer of FSL/NXP SoC sound drivers

I would like to help reviewing FSL/NXP SoC sound drivers.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Acked-by: Timur Tabi <timur@tabi.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

MAINTAINERS

@@ -4661,6 +4661,7 @@ FREESCALE SOC SOUND DRIVERS
 M:	Timur Tabi <timur@tabi.org>
 M:	Nicolin Chen <nicoleotsuka@gmail.com>
 M:	Xiubo Li <Xiubo.Lee@gmail.com>
+R:	Fabio Estevam <fabio.estevam@nxp.com>
 L:	alsa-devel@alsa-project.org (moderated for non-subscribers)
 L:	linuxppc-dev@lists.ozlabs.org
 S:	Maintained