Mostly cosmetic changes:
- reduce scope of local variabes
- wrap comment to fir 80 char limit
- check return value from imx8_esdhc_load_piggy
- drop intermediate function that only wraps a single other function

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>