hexagon: make vmem and buffer-size configurable (#22487)

* hexagon: allow host to set max vmem size

We use a sane default but it's helpful to allow for an override if needed.

* hexagon: add support for measuring vmem space and move pinned mmaping management to host

* hexagon: update vmem checks to use uint64

* hexagon: bump op buffers to 16 (matches max mmaps)

* hexagon: bump default vmem to 3.2GB

* hexagon: add support for autodetecting vmem space and some logging cleanup in that area

* hexagon: fix whitespace warnings

* Update scripts/snapdragon/adb/run-cli.sh

Co-authored-by: Pascal <admin@serveurperso.com>

* hex-adb: fix run-completion script

---------

Co-authored-by: Pascal <admin@serveurperso.com>

ggml/src/ggml-hexagon/htp/htp-ctx.h

@@ -20,7 +20,7 @@ struct htp_mmap {
     uint64_t size;
     uint64_t base;
     uint32_t fd;
-    uint32_t pinned;
+    uint32_t reserved;
 };
 
 // Scratchpad state
@@ -77,6 +77,8 @@ struct htp_context {
     atomic_bool            vtcm_valid;
     atomic_bool            vtcm_needs_release;
 
+    uint64_t               max_vmem;
+
     struct htp_ops_context octx;
 
 #ifdef HTP_HAS_HMX