Fix hardcoded timings for F450 from F205

delay_ns and delay_100ns both had hardcoded delays from the F205.
Because the F450 is faster than the F205, those delays needed
to be changed for PIO mode to work without debug on.

lib/ZuluSCSI_platform_GD32F450/ZuluSCSI_platform.cpp

@@ -36,8 +36,8 @@ void delay(unsigned long ms)
 void delay_ns(unsigned long ns)
 {
     uint32_t CNT_start = DWT->CYCCNT;
-    if (ns <= 100) return; // Approximate call overhead
-    ns -= 100;
+    if (ns <= 50) return; // Approximate call overhead
+    ns -= 50;
 
     uint32_t cycles = ((uint64_t)ns * g_ns_to_cycles) >> 32;
     while ((uint32_t)(DWT->CYCCNT - CNT_start) < cycles);
@@ -226,7 +226,6 @@ void azplatform_init()
     gpio_mode_set(GPIOB, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_3);
     gpio_output_options_set(GPIOB, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, GPIO_PIN_3);
     gpio_af_set(GPIOB, GPIO_AF_0, GPIO_PIN_3);   
-
 }
 
 void azplatform_late_init()

lib/ZuluSCSI_platform_GD32F450/ZuluSCSI_platform.h

@@ -47,7 +47,8 @@ static inline void delay_us(unsigned long us)
 // Approximate fast delay
 static inline void delay_100ns()
 {
-    asm volatile ("nop \n nop \n nop \n nop \n nop");
+//    asm volatile ("nop \n nop \n nop \n nop \n nop");
+   asm volatile ("nop \n nop \n nop \n nop \n nop \n nop");
 }
 
 // Initialize SPI and GPIO configuration