build: Drop CONFIG_SPL_BUILD guards in some cases

build: Drop CONFIG_SPL_BUILD guards in some cases

Given gcc-6.1 and later we can now safely have strings discarded when
the functions are unused.  This lets us drop certain cases of not
building something so that we don't have the strings brought in when the
code was discarded.  Simplify the code now by dropping guards we don't
need now.

Cc: Stefano Babic <[email protected]>
Cc: Fabio Estevam <[email protected]>
Cc: Chander Kashyap <[email protected]>
Cc: Thomas Abraham <[email protected]>
Cc: Vipin Kumar <[email protected]>
Cc: Wenyou Yang <[email protected]>
Signed-off-by: Tom Rini <[email protected]>