add missing GET_GOT/RESTORE_GOT pairs

These functions made global references but did not set up the GOT,
causing compilation failures in PIC mode.

Change-Id: Iac473bf46733f87eb2e001cd736af4acf73fa51d

vp8/encoder/x86/fwalsh_sse2.asm

@@ -17,6 +17,7 @@ sym(vp8_short_walsh4x4_sse2):
     push        rbp
     mov         rbp, rsp
     SHADOW_ARGS_TO_STACK 3
+    GET_GOT     rbx
     push        rsi
     push        rdi
     ; end prolog
@@ -141,6 +142,7 @@ sym(vp8_short_walsh4x4_sse2):
     ; begin epilog
     pop rdi
     pop rsi
+    RESTORE_GOT
     UNSHADOW_ARGS
     pop         rbp
     ret

vp8/encoder/x86/subtract_sse2.asm

@@ -19,6 +19,7 @@ sym(vp8_subtract_b_sse2_impl):
     push        rbp
     mov         rbp, rsp
     SHADOW_ARGS_TO_STACK 5
+    GET_GOT     rbx
     push rsi
     push rdi
     ; end prolog
@@ -64,6 +65,7 @@ sym(vp8_subtract_b_sse2_impl):
     ; begin epilog
     pop rdi
     pop rsi
+    RESTORE_GOT
     UNSHADOW_ARGS
     pop         rbp
     ret
@@ -75,6 +77,7 @@ sym(vp8_subtract_mby_sse2):
     push        rbp
     mov         rbp, rsp
     SHADOW_ARGS_TO_STACK 4
+    GET_GOT     rbx
     push rsi
     push rdi
     ; end prolog
@@ -134,6 +137,7 @@ submby_loop:
     pop rdi
     pop rsi
     ; begin epilog
+    RESTORE_GOT
     UNSHADOW_ARGS
     pop         rbp
     ret
@@ -145,6 +149,7 @@ sym(vp8_subtract_mbuv_sse2):
     push        rbp
     mov         rbp, rsp
     SHADOW_ARGS_TO_STACK 5
+    GET_GOT     rbx
     push rsi
     push rdi
     ; end prolog
@@ -338,6 +343,7 @@ sym(vp8_subtract_mbuv_sse2):
     ; begin epilog
     pop rdi
     pop rsi
+    RESTORE_GOT
     UNSHADOW_ARGS
     pop         rbp
     ret