Declare that the DMA address limitation is 32bit explicitly

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Add callback function switch_output_voltage

Different card reader has different method to switch output voltage,
so add this callback to let the card reader implement its individual function.

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Add callback function conv_clk_and_div_n

Add callback function conv_clk_and_div_n to convert between SSC clock
and its divider N.
For rtl8411, the formula to calculate SSC clock divider N is different
with the other card reader models.

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
MFD:rtsx: Fix checkpatch warning

WARNING: Avoid CamelCase: <min_N>
+	u8 N, min_N, max_N, clk_divider;

WARNING: Avoid CamelCase: <max_N>
+	u8 N, min_N, max_N, clk_divider;

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Use macro definitions to replace some variables

In function rtsx_pci_switch_clock, some variables, such as min_n, max_n,
and max_div, are not necessary. And those assigned values look very
obscure for others. It's more proper to use macro definitions here to
replace these variables.

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Try to fix the kernel panic in Thinkpad E430

Kernel would crash when inserting SD card

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>
Support more realtek cardreaders

Support rts5227/rts5249/rtl8411b

Signed-off-by: Wei WANG <wei_wang@realsil.com.cn>