Fix SoftUART putchar() return value; Should not be sign extended.
Fix SoftUART putchar() return value; Should not be sign extended.

jeditekunum/Cosa,dansut/Cosa,kc9jud/Cosa,jeditekunum/Cosa,rrobinet/Cosa,rrobinet/Cosa,dansut/Cosa,mikaelpatel/Cosa,dansut/Cosa,rrobinet/Cosa,dansut/Cosa,kc9jud/Cosa,kc9jud/Cosa,rrobinet/Cosa,kc9jud/Cosa,mikaelpatel/Cosa,mikaelpatel/Cosa,jeditekunum/Cosa,jeditekunum/Cosa,mikaelpatel/Cosa