isdn/capi: correct argument types of command_2_index

Utility function command_2_index is always called with arguments of
type u8. Adapt its declaration accordingly.
Signed-off-by: NTilman Schmidt <tilman@imap.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/isdn/capi/capiutil.c

@@ -201,7 +201,7 @@ static unsigned char *cpars[] =
 #define structTRcpyovl(x, y, l) memmove(y, x, l)
 
 /*-------------------------------------------------------*/
-static unsigned command_2_index(unsigned c, unsigned sc)
+static unsigned command_2_index(u8 c, u8 sc)
 {
 	if (c & 0x80)
 		c = 0x9 + (c & 0x0f);