ARM: shmobile: Remove stray closing parenthesis in debug description

Remove the stray closing parenthesis in the config description for the
DEBUG_RCAR_GEN2_SCIF0 option.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>