ArmPlatformPkg: Fix Ecc error 8005

This patch fixes the following Ecc reported error:
Variable name does not follow the rules:
1. First character should be upper case
2. Must contain lower case characters
3. No white space characters
4. Global variable name must start with a 'g'

Indeed, according to the EDK II C Coding Standards
Specification, s5.6.2.2 "Enumerated Types" and
s4.3.4 Function and Data Names, elements of an
enumerated type shoud be a mixed upper- and
lower-case text.

A max element is also added, as advised by
s5.6.2.2.3 of the same document.

Reference:
https://edk2-docs.gitbook.io/edk-ii-c-coding-standards-specification/

Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@arm.com>

ArmPlatformPkg/Include/Library/LcdPlatformLib.h

@@ -1,6 +1,6 @@
 /** @file
 
- Copyright (c) 2011-2018, ARM Ltd. All rights reserved.<BR>
+ Copyright (c) 2011-2020, Arm Limited. All rights reserved.<BR>
  SPDX-License-Identifier: BSD-2-Clause-Patent
 
  **/
@@ -197,14 +197,15 @@
   Register
 **/
 typedef enum {
-  LCD_BITS_PER_PIXEL_1 = 0,
-  LCD_BITS_PER_PIXEL_2,
-  LCD_BITS_PER_PIXEL_4,
-  LCD_BITS_PER_PIXEL_8,
-  LCD_BITS_PER_PIXEL_16_555,
-  LCD_BITS_PER_PIXEL_24,
-  LCD_BITS_PER_PIXEL_16_565,
-  LCD_BITS_PER_PIXEL_12_444
+  LcdBitsPerPixel_1 = 0,
+  LcdBitsPerPixel_2,
+  LcdBitsPerPixel_4,
+  LcdBitsPerPixel_8,
+  LcdBitsPerPixel_16_555,
+  LcdBitsPerPixel_24,
+  LcdBitsPerPixel_16_565,
+  LcdBitsPerPixel_12_444,
+  LcdBitsPerPixel_Max
 } LCD_BPP;
 
 // Display timing settings.