[Patch] ModuleWriteGuide: Add notes to define library instance module type

[Liming Gao <liming.gao@intel.com>]

https://bugzilla.tianocore.org/show_bug.cgi?id=834
If the library instance supports the cross module types PEIM, UEFI_DIRVER,
DXE_DRIVER. Its module type can be PEIM or UEFI_DRIVER or DXE_DRIVER.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Liming Gao <liming.gao@intel.com>
Cc: Bi Dandan <dandan.bi@intel.com>
---
 3_module_development/31_what_is_an_edk_ii_module.md | 2 ++
 3_module_development/32_creating_a_module.md        | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/3_module_development/31_what_is_an_edk_ii_module.md b/3_module_development/31_what_is_an_edk_ii_module.md
index ace8d53..9f0fe8d 100644
--- a/3_module_development/31_what_is_an_edk_ii_module.md
+++ b/3_module_development/31_what_is_an_edk_ii_module.md
@@ -78,6 +78,8 @@ EDK II defines many module types. The module type is used to:
   example, a PEIM/DXE_DRIVER type module can have "depex" section in .efi
   binary image; a UEFI_DRIVER can have .ui or .ver section in .efi binary image;
 
+* Indicate EntryPoint() or Constructor() API for different types of modules.
+
 * Indicate the suitable library instance for different types of modules. A
   library instance will point out what module types are supported in INF file.
 
diff --git a/3_module_development/32_creating_a_module.md b/3_module_development/32_creating_a_module.md
index 65a4ac7..325156f 100644
--- a/3_module_development/32_creating_a_module.md
+++ b/3_module_development/32_creating_a_module.md
@@ -197,6 +197,11 @@ instance:
   DebugLib
 ```
 
+Note: if the library supports the cross module types PEIM, UEFI_DIRVER, DXE_DRIVER.
+Its module type can be PEIM or UEFI_DRIVER or DXE_DRIVER. If it has the library
+constructor, its module type must be BASE. BASE type library constructor has no 
+the input parameter that can link to the cross driver types.
+
 ### 3.2.3 Adding a Package Dependency
 
 The [Packages] section of the INF file describes all packages dependencies of
-- 
2.13.0.windows.1