stm32f1: Adapt CONFIG_SOC to STM32Cube values

STM32Cube uses SoC defines made to reflect HW heterogeneity
that should be taken into account by SW.
Aim of this commit is to adapt values used by Zephyr to the same
diversity. This will help create new SoC values only when justified
by a real hardware difference that should be taken into account
by software.
For instance, for SoC stm32f103rb following define is used:
*STM32F103xB
Which means:
*Same SW could be used on STM32F103RB and STM32F103VB:
    same CONFIG_SOC could be used
*Different SW should be used on STMF103RB and STM32F103R4:
    different CONFIG_SOC should be used
This change focuses on stm32f1xx series.

Change-Id: I5ecfaa52952d04421b27b5e74fb71b4fc108b662
Signed-off-by: Erwan Gouriou <erwan.gouriou@linaro.org>

arch/arm/soc/st_stm32/stm32f1/Kconfig.defconfig.stm32f103xe

@@ -0,0 +1,35 @@
+# Kconfig - ST Microelectronics STM32F103VE MCU
+#
+# Copyright (c) 2016 Open-RnD Sp. z o.o.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+if SOC_STM32F103XE
+
+config SOC
+	string
+	default stm32f103xe
+
+config SRAM_SIZE
+	default 64
+
+config FLASH_SIZE
+	default 512
+
+config NUM_IRQS
+	int
+	default 68
+
+endif # SOC_STM32F103XE
+