[mips] Resolve issue with .align directive, when using clang IAS

Clang IAS does not support .align without args, concrete value is needed.

Change-Id: I50e20c374b8e88966310c0c9e6cc41eea054eb32
diff --git a/libpixelflinger/arch-mips/t32cb16blend.S b/libpixelflinger/arch-mips/t32cb16blend.S
index 236a2c9..b365fd8 100644
--- a/libpixelflinger/arch-mips/t32cb16blend.S
+++ b/libpixelflinger/arch-mips/t32cb16blend.S
@@ -178,7 +178,7 @@
 #endif
 
     .text
-    .align
+    .align 4
 
     .global scanline_t32cb16blend_mips
     .ent    scanline_t32cb16blend_mips