drm/i915/uapi: fix doc typos

Correct typo of "its".
Add commas for clarity.
Capitalize L3.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231008214942.28439-1-rdunlap@infradead.org

Author: rddunlap

include/uapi/drm/i915_drm.h

@@ -38,13 +38,13 @@ extern "C" {
  */
 
 /**
- * DOC: uevents generated by i915 on it's device node
+ * DOC: uevents generated by i915 on its device node
  *
  * I915_L3_PARITY_UEVENT - Generated when the driver receives a parity mismatch
- *	event from the gpu l3 cache. Additional information supplied is ROW,
+ *	event from the GPU L3 cache. Additional information supplied is ROW,
  *	BANK, SUBBANK, SLICE of the affected cacheline. Userspace should keep
- *	track of these events and if a specific cache-line seems to have a
- *	persistent error remap it with the l3 remapping tool supplied in
+ *	track of these events, and if a specific cache-line seems to have a
+ *	persistent error, remap it with the L3 remapping tool supplied in
  *	intel-gpu-tools.  The value supplied with the event is always 1.
  *
  * I915_ERROR_UEVENT - Generated upon error detection, currently only via