wimax/i2400m: rename misleading I2400M_PL_PAD to I2400M_PL_ALIGN

The constant is being use as an alignment factor, not as a padding
factor; made reading/reviewing the code quite confusing.

Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
diff --git a/drivers/net/wimax/i2400m/fw.c b/drivers/net/wimax/i2400m/fw.c
index 7ee1b99..26924f1 100644
--- a/drivers/net/wimax/i2400m/fw.c
+++ b/drivers/net/wimax/i2400m/fw.c
@@ -397,7 +397,7 @@
 				 unsigned int direct, unsigned int do_csum)
 {
 	int ret;
-	size_t chunk_len = ALIGN(__chunk_len, I2400M_PL_PAD);
+	size_t chunk_len = ALIGN(__chunk_len, I2400M_PL_ALIGN);
 	struct device *dev = i2400m_dev(i2400m);
 	struct {
 		struct i2400m_bootrom_header cmd;