zephyr: doc: Remove battery doc's "aforementioned"

The Zephyr battery doc states "The `vendor` and `part` references must
match an existing battery defined in [battery bindings directory]."
before a battery bindings directory is mentioned. This would likely
cause an unfamiliar reader confusion.

Remove the "aforementioned" part of the sentence.

BRANCH=none
BUG=None
TEST=gerrit view

Signed-off-by: Aaron Massey <aaronmassey@google.com>
Change-Id: I9ed2a092de239b9c67a1bababcf2b7a4499b406e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3541330
Reviewed-by: Tristan Honscheid <honscheid@google.com>

Author: aaronemassey

docs/zephyr/zephyr_battery.md

@@ -53,8 +53,7 @@ Example:
 Here `vendor_part` will be the default battery type. If this node label is
 present in the overlay, the [DEFAULT_BATTERY_TYPE] is set in the battery shim
 code with the labeled battery type. The `vendor` and `part` references must
-match an existing battery defined in the aforementioned [battery bindings
-directory].
+match an existing battery defined in [battery bindings directory].
 
 ##### Add the battery present GPIO node as a child of `named-gpios`