Suppress MIPS32 assembler warnings

Suppressing "no .cprestore pseudo-op used in PIC code".
Suppressing "used $at without .set noat".
Fixing some typos.

Change-Id: I45267890b070cee3dd7f3708cf73e157a08f798e
diff --git a/runtime/arch/mips/jni_entrypoints_mips.S b/runtime/arch/mips/jni_entrypoints_mips.S
index 3558efd..5c95071 100644
--- a/runtime/arch/mips/jni_entrypoints_mips.S
+++ b/runtime/arch/mips/jni_entrypoints_mips.S
@@ -38,7 +38,8 @@
     .cfi_rel_offset 5, 4
     sw    $a0, 0($sp)
     .cfi_rel_offset 4, 0
-    jal   artFindNativeMethod   # (Thread*)
+    la    $t9, artFindNativeMethod
+    jalr  $t9                   # (Thread*)
     move  $a0, $s1              # pass Thread::Current()
     lw    $a0, 0($sp)           # restore registers from stack
     lw    $a1, 4($sp)