net: Remove CONFIG_SYS_DIRECT_FLASH_TFTP

No platforms enable the functionality to tftp directly to NOR flash, and
this is discouraged by the documentation.  Remove this code.  Further,
this highlights an oddity of the code.  Un-indent the start of this
function.

Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Ramon Fried <rfried.dev@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
3 files changed