adb: Set max socket sizes to larger values.

This improves performance of push/pull.

Test: adb push/pull multi GB files.
Bug: 31722483
Change-Id: Ia01574c3db6a740d7a7e64ba1f5bc1fc279fb3f6
diff --git a/adb/adb.h b/adb/adb.h
index 6a38f18..a30e297 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -34,6 +34,8 @@
 constexpr size_t MAX_PAYLOAD_V2 = 256 * 1024;
 constexpr size_t MAX_PAYLOAD = MAX_PAYLOAD_V2;
 
+constexpr size_t LINUX_MAX_SOCKET_SIZE = 4194304;
+
 #define A_SYNC 0x434e5953
 #define A_CNXN 0x4e584e43
 #define A_OPEN 0x4e45504f