Update on "[ET-VK] Enforce GPU buffer limit when partitioning"

## Context

In Vulkan, there is a limit on the number of elements a GPU buffer can have. If a GPU buffer exceeds this limit, then the API will either produce an error or undefined behaviour will ensue.

## Changes

Along with `texture_limits`, introduce a configurable `buffer_limit` entry in the partitioner configuration.

Differential Revision: [D65899828](https://our.internmc.facebook.com/intern/diff/D65899828/)

[ghstack-poisoned]

Author: SS-JIA

backends/vulkan/utils.py

@@ -87,7 +87,7 @@ def is_tensor_node(node: torch.fx.Node) -> bool:
 ImageExtents = Tuple[int, int, int]
 
 DEFAULT_TEXTURE_LIMITS = (16384, 16384, 2048)
-DEFAULT_BUFFER_LIMIT = 134217728
+DEFAULT_BUFFER_LIMIT = 128 * (1024 * 1024)
 
 
 class PackedDim(IntEnum):