common: env_sf: Add exclamation mark

common: env_sf: Add exclamation mark

Add exclamation mark to the errmsg, when error and set_default_env.

Signed-off-by: Peng Fan <[email protected]>
Cc: Mario Schuknecht <[email protected]>
Cc: Vignesh R <[email protected]>
Cc: Jagan Teki <[email protected]>
Cc: Ravi Babu <[email protected]>
Cc: York Sun <[email protected]>
Cc: Tom Rini <[email protected]>
Reviewed-by: Tom Rini <[email protected]>