Fix pixel_gradient_info allocation

In very rare cases, the work thread data needs to be re-allocated, but
the condition in is_gradient_caching_for_hog_enabled() is not true.
Thus, this results in no pixel_gradient_info data allocated for work
threads and the memory write violation happens. This change fixes this
issue.

Bug: b/559019046
Change-Id: I38b2285aeffe1732239cb2401b61a3654f386896
(cherry picked from commit f9a09995618828dba5a3f154f30d60779e4acd33)

av1/encoder/ethread.c

diff --git a/av1/encoder/ethread.c b/av1/encoder/ethread.c
index d46b3ee..53513f8 100644
--- a/av1/encoder/ethread.c
+++ b/av1/encoder/ethread.c
@@ -1039,12 +1039,10 @@
           }
         }
 
-        if (is_gradient_caching_for_hog_enabled(ppi->cpi)) {
-          const int plane_types = PLANE_TYPES >> ppi->seq_params.monochrome;
-          AOM_CHECK_MEM_ERROR(&ppi->error, td->pixel_gradient_info,
-                              aom_malloc(sizeof(*td->pixel_gradient_info) *
-                                         plane_types * MAX_SB_SQUARE));
-        }
+        const int plane_types = PLANE_TYPES >> ppi->seq_params.monochrome;
+        AOM_CHECK_MEM_ERROR(&ppi->error, td->pixel_gradient_info,
+                            aom_malloc(sizeof(*td->pixel_gradient_info) *
+                                       plane_types * MAX_SB_SQUARE));
 
         if (is_src_var_for_4x4_sub_blocks_caching_enabled(ppi->cpi)) {
           const BLOCK_SIZE sb_size = ppi->cpi->common.seq_params->sb_size;