lib/core: Fix power disable process for ADCS

Fixes an issue where disabling the power control for ADCS was not
working correctly. This issue had been resolved on the MAIN board
in the following commit but had not been deployed to ADCS.

  commit f97719a
    hwtest/main: Fix Power disable not working

Signed-off-by: Takuya Sasaki <takuya.sasaki@spacecubics.com>

lib/core/pwrctrl_adcs.c

@@ -34,7 +34,10 @@ void sc_adcs_power_enable(uint8_t target_bit)
 
 void sc_adcs_power_disable(uint8_t target_bit)
 {
-	sys_clear_bits(SCADCS_ADCS_BASE_ADDR + SCADCS_PCR_OFFSET, SCADCS_PCR_KEYCODE | target_bit);
+	uint32_t val = sys_read32(SCADCS_ADCS_BASE_ADDR + SCADCS_PCR_OFFSET);
+
+	val = SCADCS_PCR_KEYCODE | (val & ~target_bit);
+	sys_write32(val, SCADCS_ADCS_BASE_ADDR + SCADCS_PCR_OFFSET);
 }
 
 void sc_adcs_imu_reset(void)