MIPS: remove .MIPS.abiflags section

The abiflags data is only used to communicate ABI information to a
program loader -- you can see what info is stored with readelf -A.
Dropping it shaves 24 bytes off of every binary (including plugins).

Change-Id: Iae78eeffe5c840ff67717707fb94821d24aac8ec

apps/plugins/plugin.lds

@@ -299,6 +299,7 @@ SECTIONS
     {
         *(.eh_frame)
 #ifdef CPU_MIPS
+        *(.MIPS.abiflags)
         *(.rel.dyn)
 #endif
     }

firmware/target/mips/ingenic_jz47xx/app.lds

@@ -111,6 +111,7 @@ SECTIONS
 
     /DISCARD/ :
     {
+        *(.MIPS.abiflags);
         *(.eh_frame);
         *(.rel.dyn);
     }

firmware/target/mips/ingenic_jz47xx/boot.lds

@@ -91,4 +91,11 @@ SECTIONS
          . += 0x400;
          irqstackend = .;
     } > IRAM
+
+    /DISCARD/ :
+    {
+        *(.MIPS.abiflags);
+        *(.eh_frame);
+        *(.rel.dyn);
+    }
 }

firmware/target/mips/ingenic_x1000/app.lds

@@ -113,6 +113,7 @@ SECTIONS
 
     /DISCARD/ :
     {
+        *(.MIPS.abiflags);
         *(.eh_frame);
         *(.rel.dyn);
     }

firmware/target/mips/ingenic_x1000/spl.lds

@@ -57,4 +57,11 @@ SECTIONS
     {
         *(.sdram);
     } > DRAM
+
+    /DISCARD/ :
+    {
+        *(.MIPS.abiflags);
+        *(.eh_frame);
+        *(.rel.dyn);
+    }
 }