Texture fetching

[parbenc]

add page explaining texture fetching in HIP

[neon60]

@parbenc please link the following pages in the document:

• https://rocm.docs.amd.com/projects/HIP/en/latest/doxygen/html/group___texture.html
• https://rocm.docs.amd.com/projects/HIP/en/latest/understand/programming_model_reference.html

[neon60]

Can we alse describe the different modes here:

https://rocm.docs.amd.com/projects/HIP/en/latest/doxygen/html/texture__types_8h.html

hipAddressModeWrap hipAddressModeClamp   hipAddressModeMirror   hipAddressModeBorder

[neon60]

Please add figures for the different address and filter modes.