staging: gs_fpgaboot: remove unnecessary return statements

This fixes "void function return statements are not generally useful"
warnings from checkpatch.pl.
Signed-off-by: Michał Bartoszkiewicz <mbartoszkiewicz@gmail.com>
Reviewed-by: Insop Song <insop.song@gainspeed.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gs_fpgaboot/io.c

@@ -251,17 +251,14 @@ int xl_init_io(void)
 
 void xl_program_b(int32_t i)
 {
-	return;
 }
 
 void xl_rdwr_b(int32_t i)
 {
-	return;
 }
 
 void xl_csi_b(int32_t i)
 {
-	return;
 }
 
 int xl_get_init_b(void)
@@ -276,17 +273,14 @@ int xl_get_done_b(void)
 
 static inline void byte0_out(unsigned char data)
 {
-	return;
 }
 
 static inline void byte1_out(unsigned char data)
 {
-	return;
 }
 
 static inline void xl_cclk_b(int32_t i)
 {
-	return;
 }
 
 /*