STM32F1 HAL Fixes (#10999)

- Enable / disable interrupts with `__iSeiRetVal` / `__iCliRetVal`
- Add STM32F1 to Travis CI tests

.travis.yml

   - update_defaults
   - opt_enable VIKI2 SDSUPPORT
   - build_marlin_pio ${TRAVIS_BUILD_DIR} ${TEST_PLATFORM}
+
+  #############################
+  # STM32F1 default config test
+  #############################
+
+  - export TEST_PLATFORM="-e STM32F1"
+  - restore_configs
+  - opt_set MOTHERBOARD BOARD_STM32F1R
+  - update_defaults
+  - build_marlin_pio ${TRAVIS_BUILD_DIR} ${TEST_PLATFORM}

Marlin/src/HAL/HAL_STM32F1/HAL.h

 // --------------------------------------------------------------------------
 
 #include <stdint.h>
-
+#include <libmaple/atomic.h>
 #include <Arduino.h>
 
 // --------------------------------------------------------------------------
   #define analogInputToDigitalPin(p) (p)
 #endif
 
-#define CRITICAL_SECTION_START  uint32_t primask = __get_PRIMASK(); __disable_irq()
-#define CRITICAL_SECTION_END    if (!primask) __enable_irq()
-#define ISRS_ENABLED() (!__get_PRIMASK())
-#define ENABLE_ISRS()  __enable_irq()
-#define DISABLE_ISRS() __disable_irq()
+#define CRITICAL_SECTION_START  uint32_t primask = __get_primask(); (void)__iCliRetVal()
+#define CRITICAL_SECTION_END    if (!primask) (void)__iSeiRetVal()
+#define ISRS_ENABLED() (!__get_primask)
+#define ENABLE_ISRS()  ((void)__iSeiRetVal())
+#define DISABLE_ISRS() ((void)__iCliRetVal())
 
 // On AVR this is in math.h?
 #define square(x) ((x)*(x))