Documentation: dmaengine: Correct reference to glReadPixels()

The author very likely meant "glReadPixels()" instead of
"glReadpielx()", which does not appear in the OpenGL API.

https://registry.khronos.org/OpenGL-Refpages/gl4/html/glReadPixels.xhtml

Signed-off-by: Nathan Lynch <nathan.lynch@amd.com>
Link: https://lore.kernel.org/r/20241010-doc-dmaengine-glreadpixels-v1-1-8202e5834b13@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: nathanlynch

Documentation/driver-api/dmaengine/provider.rst

@@ -172,8 +172,8 @@ Currently, the types available are:
   - It's usually used for copying pixel data between host memory and
     memory-mapped GPU device memory, such as found on modern PCI video graphics
     cards. The most immediate example is the OpenGL API function
-    ``glReadPielx()``, which might require a verbatim copy of a huge framebuffer
-    from local device memory onto host memory.
+    ``glReadPixels()``, which might require a verbatim copy of a huge
+    framebuffer from local device memory onto host memory.
 
 - DMA_XOR