staging: rtl8723bs: remove set but not used variable 'pszBBRegMpFile'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/staging/rtl8723bs/hal/rtl8723b_phycfg.c: In function phy_BB8723b_Config_ParaFile:
drivers/staging/rtl8723bs/hal/rtl8723b_phycfg.c:436:77:
 warning: variable pszBBRegMpFile set but not used [-Wunused-but-set-variable]

It is never used so can be removed.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20190726140734.39564-1-yuehaibing@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/hal/rtl8723b_phycfg.c

@@ -431,14 +431,12 @@ static int phy_BB8723b_Config_ParaFile(struct adapter *Adapter)
 	u8 sz8723BBRegFile[] = RTL8723B_PHY_REG;
 	u8 sz8723AGCTableFile[] = RTL8723B_AGC_TAB;
 	u8 sz8723BBBRegPgFile[] = RTL8723B_PHY_REG_PG;
-	u8 sz8723BBRegMpFile[] = RTL8723B_PHY_REG_MP;
 	u8 sz8723BRFTxPwrLmtFile[] = RTL8723B_TXPWR_LMT;
-	u8 *pszBBRegFile = NULL, *pszAGCTableFile = NULL, *pszBBRegPgFile = NULL, *pszBBRegMpFile = NULL, *pszRFTxPwrLmtFile = NULL;
+	u8 *pszBBRegFile = NULL, *pszAGCTableFile = NULL, *pszBBRegPgFile = NULL, *pszRFTxPwrLmtFile = NULL;
 
 	pszBBRegFile = sz8723BBRegFile;
 	pszAGCTableFile = sz8723AGCTableFile;
 	pszBBRegPgFile = sz8723BBBRegPgFile;
-	pszBBRegMpFile = sz8723BBRegMpFile;
 	pszRFTxPwrLmtFile = sz8723BRFTxPwrLmtFile;
 
 	/*  Read Tx Power Limit File */