ARM: OMAP2+: Fix section warnings for hsmmc_init_one

Otherwise we can get the following error depending on
the compiler:

WARNING: arch/arm/mach-omap2/built-in.o(.text+0xafe0):
Section mismatch in reference from the function omap_hsmmc_init_one()
to the function .init.text:omap_hsmmc_pdata_init()
The function omap_hsmmc_init_one() references
the function __init omap_hsmmc_pdata_init().
This is often because omap_hsmmc_init_one lacks a __init
annotation or the annotation of omap_hsmmc_pdata_init is wrong.

Signed-off-by: Tony Lindgren <tony@atomide.com>