staging: rtl8723bs: remove shadowed variable in sdio_halinit

staging: rtl8723bs: remove shadowed variable in sdio_halinit

The variable 'bMacPwrCtrlOn' was redeclared in the function
CardEnable, shadowing a variable of the same name declared at the
top of the function (line 21).

Remove the redundant 'u8' type declaration to use the existing outer
variable and resolve a -Wshadow warning.

Signed-off-by: Haroen Tmimi <tmimiharoen@gmail.com>
Reviewed-by: Ethan Tidmore <ethantidmore06@gmail.com>
Link: https://patch.msgid.link/20260210185630.54577-1-tmimiharoen@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>