misc: rtsx: Fix clang -Wsometimes-uninitialized in rts5261_init_from_hw()

Clang warns:

  drivers/misc/cardreader/rts5261.c:406:13: error: variable 'setting_reg2' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
          } else if (efuse_valid == 0) {
                     ^~~~~~~~~~~~~~~~
  drivers/misc/cardreader/rts5261.c:412:30: note: uninitialized use occurs here
          pci_read_config_dword(pdev, setting_reg2, &lval2);
                                      ^~~~~~~~~~~~

efuse_valid == 1 is not a valid value so just return early from the
function to avoid using setting_reg2 uninitialized.

Fixes: b1c5f30 ("misc: rtsx: add rts5261 efuse function")
Reported-by: Dan Carpenter <[email protected]>
Reported-by: kernel test robot <[email protected]>
Reported-by: Tom Rix <[email protected]>
Suggested-by: Ricky WU <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: nathanchance

drivers/misc/cardreader/rts5261.c

@@ -407,6 +407,8 @@ static void rts5261_init_from_hw(struct rtsx_pcr *pcr)
 		// default
 		setting_reg1 = PCR_SETTING_REG1;
 		setting_reg2 = PCR_SETTING_REG2;
+	} else {
+		return;
 	}
 
 	pci_read_config_dword(pdev, setting_reg2, &lval2);