riscv: cosmetic: Reword do_reset() printf message.

The Sentence "reset unsupported yet" is not
grammatically correct and should say
"reset not supported yet" instead.

Suggested-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Signed-off-by: Rick Chen <rick@andestech.com>
1 file changed