boards: olimex stm32-e407: Fix pin number of RESET

According to STM32-E407.pdf (Revision I, June 2017), CON1 RST is
connected to processor pin #25, not #23.

Signed-off-by: Reto Schneider <[email protected]>

Author: rettichschnidi

boards/arm/olimex_stm32_e407/doc/olimex_stm32_e407.rst

@@ -133,7 +133,7 @@ CON1 power
 +-------+--------------+-------------------------+
 | Pin   | Signal Name  | STM32F407 Pin#          |
 +=======+==============+=========================+
-| RST   | RESET        | 23                      |
+| RST   | RESET        | 25                      |
 +-------+--------------+-------------------------+
 | 3V3   | VCC (3V3)    | N/A                     |
 +-------+--------------+-------------------------+