platform/prime_hub: fix missing PLLR init

This fixes missing init values in the osc clock init. This was found
in b094823 which broke dual boot due to zero initializing `osc_init`.

Since we are initializing all values, we don't need to zero initialize.

Partially reverts commit 463c9e9.

lib/pbio/platform/prime_hub/platform.c

@@ -698,23 +698,33 @@ extern uint32_t *_fw_isr_vector_src;
 
 // Called from assembly code in startup.s
 void SystemInit(void) {
+    // enable 8-byte stack alignment for IRQ handlers, in accord with EABI
+    SCB->CCR |= SCB_CCR_STKALIGN_Msk;
 
-    RCC_OscInitTypeDef osc_init;
-    RCC_ClkInitTypeDef clk_init;
+    // since the firmware starts at 0x08008000, we need to set the vector table offset
+    SCB->VTOR = (uint32_t)&_fw_isr_vector_src;
+
+    // bootloader disables interrupts
+    __enable_irq();
 
     // Using external 16Mhz oscillator
+    RCC_OscInitTypeDef osc_init;
     osc_init.OscillatorType = RCC_OSCILLATORTYPE_HSE;
     osc_init.HSEState = RCC_HSE_ON;
+    osc_init.LSEState = RCC_LSE_OFF;
     osc_init.HSIState = RCC_HSI_OFF;
+    osc_init.LSIState = RCC_LSI_OFF;
     osc_init.PLL.PLLState = RCC_PLL_ON;
     osc_init.PLL.PLLSource = RCC_PLLSOURCE_HSE;
     osc_init.PLL.PLLM = 8; // VCO_IN 2MHz (16MHz / 8)
     osc_init.PLL.PLLN = 96; // VCO_OUT 192MHz (2MHz * 96)
     osc_init.PLL.PLLP = RCC_PLLP_DIV2; // PLLCLK 96MHz (not using max of 100 because of USB)
     osc_init.PLL.PLLQ = 4; // 48MHz USB clock
+    osc_init.PLL.PLLR = 2; // 96MHz system clock
 
     HAL_RCC_OscConfig(&osc_init);
 
+    RCC_ClkInitTypeDef clk_init;
     clk_init.ClockType = RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2;
     clk_init.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
     clk_init.AHBCLKDivider = RCC_SYSCLK_DIV1;  // HCLK 96MHz
@@ -723,15 +733,6 @@ void SystemInit(void) {
 
     HAL_RCC_ClockConfig(&clk_init, FLASH_LATENCY_5);
 
-    // enable 8-byte stack alignment for IRQ handlers, in accord with EABI
-    SCB->CCR |= SCB_CCR_STKALIGN_Msk;
-
-    // since the firmware starts at 0x08008000, we need to set the vector table offset
-    SCB->VTOR = (uint32_t)&_fw_isr_vector_src;
-
-    // bootloader disables interrupts
-    __enable_irq();
-
     // If we are running dual boot, jump to other firmware if no buttons are pressed
     pbio_platform_dual_boot();