[U-Boot] SZ_* errors compiling mmc master branch

[Stephen Warren]

Jaehoon,

When building git://git.denx.de/u-boot-mmc.git master for sandbox, I see 
the following error, and many more like it:

> Building current source for 3 boards (3 threads, 4 jobs per thread)
>    sandbox:  +   sandbox_noblk
> +drivers/mmc/mmc.c:25:6: error: ‘SZ_16K’ undeclared here (not in a function)
> +  0,  SZ_16K / 512,  SZ_32K / 512,
> +      ^
> +drivers/mmc/mmc.c:25:21: error: ‘SZ_32K’ undeclared here (not in a function)
> +                     ^