ARM: imx/pcm038: make regulator platform data static

This fixes the following sparse warning:

	arch/arm/mach-imx/pcm970-baseboard.c:203:30: warning: symbol 'pcm970_sja1000_platform_data' was not declared. Should it be static?

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>