drivers/adc: Use mutexlock to replace critical section protection

[zkkkk12]

Use mutexlock to replace critical section protection when using adc_isr_thread

Note: Please adhere to Contributing Guidelines.

Summary
The modification replaces critical section protection with mutex locks in ADC driver functions when CONFIG_ADC_ISR_THREAD is enabled, ensuring thread-safe hardware operations without unnecessarily disabling interrupts.

Impact
Benefits:

Reduced Interrupt Latency: Interrupts remain enabled during hardware operations
Better System Throughput: Other interrupts can still be serviced
Improved Real-time Performance: Shorter critical sections mean better determinism
Testing
The ADC function was tested and verified to be working correctly using NuttX's built-in adc_drivers.（apps/examples/adc）
Test Results：
Test results: When you input adc -p in the nsh terminal, the pin corresponding to channel adc0 is shown below.

[core2] adc -p
[core2] adc_main:g_adcstate.count: 3
[core2] adc_main: Hardware initialized. Opening the ADC device: /dev/adc0
[core2] Sample:
[core2] 1: channel: 32 value: 986
[core2] 2: channel: 34 value: 933