Remove interrupt disable around flash operations

All interrupt service routines are supposed to be in IRAM now, so there
is no need to keep interrupts disabled while doing flash operations.
Remove the IRQ disable/enable from the ESP.flash* methods.

Related to esp8266#5568

Author: earlephilhower

cores/esp8266/Esp.cpp

@@ -572,9 +572,7 @@ bool EspClass::updateSketch(Stream& in, uint32_t size, bool restartOnFail, bool
 static const int FLASH_INT_MASK = ((B10 << 8) | B00111010);
 
 bool EspClass::flashEraseSector(uint32_t sector) {
-    ets_isr_mask(FLASH_INT_MASK);
     int rc = spi_flash_erase_sector(sector);
-    ets_isr_unmask(FLASH_INT_MASK);
     return rc == 0;
 }
 
@@ -622,7 +620,6 @@ static int spi_flash_write_puya(uint32_t offset, uint32_t *data, size_t size) {
 #endif
 
 bool EspClass::flashWrite(uint32_t offset, uint32_t *data, size_t size) {
-    ets_isr_mask(FLASH_INT_MASK);
     int rc = 0;
 #if PUYA_SUPPORT
     if (getFlashChipVendorId() == SPI_FLASH_VENDOR_PUYA) {
@@ -633,14 +630,11 @@ bool EspClass::flashWrite(uint32_t offset, uint32_t *data, size_t size) {
     {
         rc = spi_flash_write(offset, data, size);
     }
-    ets_isr_unmask(FLASH_INT_MASK);
     return rc == 0;
 }
 
 bool EspClass::flashRead(uint32_t offset, uint32_t *data, size_t size) {
-    ets_isr_mask(FLASH_INT_MASK);
     int rc = spi_flash_read(offset, (uint32_t*) data, size);
-    ets_isr_unmask(FLASH_INT_MASK);
     return rc == 0;
 }