util/spkmodem_recv: Tidy up global variables

They do not need to be initialised zero, because
global variables are always zero by default,
unless set differently by the programmer.

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/spkmodem_recv/spkmodem-recv.c

@@ -23,9 +23,7 @@
 
 signed short frame[2 * SAMPLES_PER_FRAME];
 signed short pulse[2 * SAMPLES_PER_FRAME];
-int f1, f2;
-int lp = 0;
-int ascii_bit = 7;
+int f1, f2, lp, ascii_bit = 7;
 char ascii = 0;
 
 void handle_audio(void);