c89: get rid of designated initializers in common code

Signed-off-by: Petro Karashchenko <petro.karashchenko@gmail.com>

drivers/input/button_lower.c

@@ -60,9 +60,10 @@ static uint32_t g_btnnum;
 
 static const struct btn_lowerhalf_s g_btnlower =
 {
-  .bl_supported  = btn_supported,
-  .bl_buttons    = btn_buttons,
-  .bl_enable     = btn_enable,
+  btn_supported,        /* bl_supported */
+  btn_buttons,          /* bl_buttons */
+  btn_enable,           /* bl_enable */
+  NULL                  /* bl_write */
 };
 
 /* Current interrupt handler and argument */

drivers/input/cypress_mbr3108.c

@@ -240,18 +240,12 @@ static int mbr3108_i2c_write(FAR struct mbr3108_dev_s *dev, uint8_t reg,
   struct i2c_msg_s msgv[2] =
   {
     {
-      .frequency = CONFIG_MBR3108_I2C_FREQUENCY,
-      .addr      = dev->addr,
-      .flags     = 0,
-      .buffer    = &reg,
-      .length    = 1
+      CONFIG_MBR3108_I2C_FREQUENCY,
+      dev->addr, 0, &reg, sizeof(reg)
     },
     {
-      .frequency = CONFIG_MBR3108_I2C_FREQUENCY,
-      .addr      = dev->addr,
-      .flags     = I2C_M_NOSTART,
-      .buffer    = (void *)buf,
-      .length    = buflen
+      CONFIG_MBR3108_I2C_FREQUENCY,
+      dev->addr, I2C_M_NOSTART, buf, buflen
     }
   };
 
@@ -294,18 +288,12 @@ static int mbr3108_i2c_read(FAR struct mbr3108_dev_s *dev, uint8_t reg,
   struct i2c_msg_s msgv[2] =
   {
     {
-      .frequency = CONFIG_MBR3108_I2C_FREQUENCY,
-      .addr      = dev->addr,
-      .flags     = 0,
-      .buffer    = &reg,
-      .length    = 1
+      CONFIG_MBR3108_I2C_FREQUENCY,
+      dev->addr, 0, &reg, sizeof(reg)
     },
     {
-      .frequency = CONFIG_MBR3108_I2C_FREQUENCY,
-      .addr      = dev->addr,
-      .flags     = I2C_M_READ,
-      .buffer    = buf,
-      .length    = buflen
+      CONFIG_MBR3108_I2C_FREQUENCY,
+      dev->addr, I2C_M_READ, buf, buflen
     }
   };