video_core: Adjust `NUM` macro to avoid Clang warning

The previous definition was:

    #define NUM(field_name) (sizeof(Maxwell3D::Regs::field_name) / sizeof(u32))

In cases where `field_name` happens to refer to an array, Clang thinks
`sizeof(an array value) / sizeof(a type)` is an instance of the idiom
where `sizeof` is used to compute an array length.  So it thinks the
type in the denominator ought to be the array element type, and warns if
it isn't, assuming this is a mistake.

In reality, `NUM` is not used to get array lengths at all, so there is no
mistake.  Silence the warning by applying Clang's suggested workaround
of parenthesizing the denominator.

src/video_core/dirty_flags.cpp

@@ -9,7 +9,7 @@
 #include "video_core/dirty_flags.h"
 
 #define OFF(field_name) MAXWELL3D_REG_INDEX(field_name)
-#define NUM(field_name) (sizeof(::Tegra::Engines::Maxwell3D::Regs::field_name) / sizeof(u32))
+#define NUM(field_name) (sizeof(::Tegra::Engines::Maxwell3D::Regs::field_name) / (sizeof(u32)))
 
 namespace VideoCommon::Dirty {
 

src/video_core/renderer_opengl/gl_state_tracker.cpp

@@ -13,7 +13,7 @@
 #include "video_core/renderer_opengl/gl_state_tracker.h"
 
 #define OFF(field_name) MAXWELL3D_REG_INDEX(field_name)
-#define NUM(field_name) (sizeof(Maxwell3D::Regs::field_name) / sizeof(u32))
+#define NUM(field_name) (sizeof(Maxwell3D::Regs::field_name) / (sizeof(u32)))
 
 namespace OpenGL {
 

src/video_core/renderer_vulkan/vk_state_tracker.cpp

@@ -14,7 +14,7 @@
 #include "video_core/renderer_vulkan/vk_state_tracker.h"
 
 #define OFF(field_name) MAXWELL3D_REG_INDEX(field_name)
-#define NUM(field_name) (sizeof(Maxwell3D::Regs::field_name) / sizeof(u32))
+#define NUM(field_name) (sizeof(Maxwell3D::Regs::field_name) / (sizeof(u32)))
 
 namespace Vulkan {